Practice neco geography 2023 Past Questions | Edcrib

Question 1 View Details

A location records the following average monthly rainfall (in mm): Jan 45, Feb 55, Mar 120, Apr 150, May 200, Jun 250, Jul 300, Aug 280, Sep 200, Oct 150, Nov 100, Dec 80. The total annual precipitation is \(P\) mm. According to the Köppen climate classification, a tropical monsoon climate (Am) occurs when the driest month has precipitation less than 60 mm but greater than \(100 - \frac{P}{25}\). Determine the climate type (Af, Am, or Aw) for this location.

A. Aw

B. As

C. Af

Correct D. Am

Correct Answer: D

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Question 2 View Details

On a certain day, the probability that it rains on Monday is 0.30. If it rains on Monday, the probability that it rains on Tuesday is 0.60; if it does not rain on Monday, the probability that it rains on Tuesday is 0.20. What is the probability that it rains on at least one of the two days? Express your answer as a decimal to two places.

A. 0.62

B. 0.50

C. 0.38

Correct D. 0.44

Correct Answer: D

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Question 3 View Details

A rock sample consists of 40% quartz (Mohs hardness 7), 30% feldspar (hardness 6), 20% mica (hardness 2.5) and 10% calcite (hardness 3). Compute the weighted average hardness of the rock and state whether the rock, as a whole, would be able to scratch glass (hardness 5.5). Give the average hardness to one decimal place.

A. Average hardness 5.2; cannot scratch glass

B. Average hardness 5.6; cannot scratch glass

C. Average hardness 5.4; can scratch glass

Correct D. Average hardness 5.4; cannot scratch glass

Correct Answer: D

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Question 4 View Details

A town had a population of 50,000 in the year 2000. Each year the natural increase (births minus deaths) adds 2% to the population, while net migration results in a loss of 500 persons per year. Assuming these rates remain constant, what is the estimated population in the year 2020? Round to the nearest whole number.

A. 63000

Correct B. 62150

C. 61800

D. 62500

Correct Answer: B

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Question 5 View Details

A river descends from point A at an elevation of 350 m to point B at 150 m. The straight‑line distance between A and B is 20 km, but the river follows a meandering channel of length 25 km. Calculate the average gradient of the river in metres per kilometre using the actual channel length, and classify the gradient as gentle (<4 m/km), moderate (4-25 m/km) or steep (>25 m/km).

A. 30 m/km, steep

Correct B. 8 m/km, moderate

C. 13 m/km, moderate

D. 10 m/km, moderate

Correct Answer: B

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Question 6 View Details

A catchment of 25 km\(^2\) has 40 % forest (runoff coefficient 0.15) and 60 % agriculture (runoff coefficient 0.30). A design storm of 30 mm in 2 h is expected. Using the Rational method, estimate the peak discharge in m\(^3\) s\(^{-1}\).

A. 15.23

B. 20.45

Correct C. 17.68

D. 13.80

Correct Answer: C

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Question 7 View Details

Two regions have the data below (mean monthly temperature in °C and rainfall in mm):\nRegion A: T = [24,25,26,27,28,29,30,30,29,28,26,25]; P = [80,70,60,50,40,30,20,20,30,50,70,80].\nRegion B: T = [28,29,30,31,32,33,34,34,33,32,30,28]; P = [20,20,30,40,60,80,100,100,80,60,40,30].\nUsing the Thornthwaite method, compute the annual potential evapotranspiration (PET) for each region, then calculate the aridity index \(AI = P_{annual}/PET\). Classify each region as arid (AI < 0.5), semi‑arid (0.5 ≤ AI < 0.65) or sub‑humid (AI ≥ 0.65).

Correct A. Region A: arid; Region B: arid

B. Region A: arid; Region B: semi‑arid

C. Region A: sub‑humid; Region B: arid

D. Region A: semi‑arid; Region B: arid

Correct Answer: A

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Question 8 View Details

A river is 120 km long and drops 600 m from source to mouth. Its average discharge is 150 m\(^3\) s\(^{-1}\). The channel can be approximated as a rectangular cross‑section 30 m wide and 3 m deep. Using Manning's equation with roughness coefficient \(n=0.035\), determine the average slope, classify the river stage (youthful, mature or old) based on the slope, and estimate the travel time of a water particle from source to mouth.

A. Average slope = 0.003 (0.3 %); river is old; travel time ≈ 12 hours

Correct B. Average slope = 0.005 (0.5 %); river is mature; travel time ≈ 9 hours

C. Average slope = 0.010 (1.0 %); river is youthful; travel time ≈ 5 hours

D. Average slope = 0.008 (0.8 %); river is youthful; travel time ≈ 6 hours

Correct Answer: B

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Question 9 View Details

A city had a population of 1.2 million in 2010. The natural increase (births minus deaths) is 2.1 % per year and net migration is -0.4 % per year. Assuming the rates remain constant, estimate the population in 2025 and state the average annual net growth rate over the 15‑year period.

A. 1.48 million (average net growth ≈ 1.55 %)

B. 1.60 million (average net growth ≈ 1.80 %)

C. 1.52 million (average net growth ≈ 1.62 %)

Correct D. 1.54 million (average net growth ≈ 1.69 %)

Correct Answer: D

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Question 10 View Details

A proposed road segment of 50 km will cost \(\text{₦}120\) billion to construct. Expected annual traffic is 12 000 vehicles, each paying a toll of \(\text{₦}2{,}500\). Operating cost per vehicle is \(\text{₦}500\) and fixed annual maintenance is \(\text{₦}1.5\) billion. Using a discount rate of 8 % and a 20‑year analysis period, calculate the net present value (NPV) of the road project. An alternative railway would cost \(\text{₦}150\) billion, carry 8 000 passengers per year at a fare of \(\text{₦}5{,}000\) each, with operating cost \(\text{₦}1{,}200\) per passenger and fixed maintenance \(\text{₦}2\) billion per year. Compute the railway's NPV under the same assumptions and state which option is financially preferable.

A. Road NPV ≈ -₦140.2 billion; Railway NPV ≈ -₦160.5 billion; road is relatively better but both are unviable

B. Road NPV ≈ -₦120.0 billion; Railway NPV ≈ -₦150.0 billion; road is relatively better but both are unviable

Correct C. Road NPV ≈ -₦134.5 billion; Railway NPV ≈ -₦169.3 billion; road is relatively better but both are unviable

D. Road NPV ≈ -₦130.0 billion; Railway NPV ≈ -₦180.0 billion; road is relatively better but both are unviable

Correct Answer: C

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Question 11 View Details

A farmer has 12 ha of land to allocate between maize and cassava. Maize yields \(3.2\) t/ha and sells for \(45{,}000\) Naira per ton; its production cost is \(30{,}000\) Naira per ha. Cassava yields \(20\) t/ha and sells for \(12{,}000\) Naira per ton; its production cost is \(20{,}000\) Naira per ha. The government offers a 25% fertilizer subsidy for maize if the area planted to maize exceeds \(4\) ha, reducing the maize cost per ha to \(22{,}500\) Naira. A processing plant pays a bonus of \(5{,}000\) Naira per ton of cassava if total cassava production exceeds \(150\) t. At least \(2\) ha must be allocated to each crop. Determine the allocation (ha of maize and ha of cassava) that maximises net profit and state the maximum net profit.

Correct A. 2 ha of maize, 10 ha of cassava; maximum net profit = ₦3,428,000

B. 5 ha of maize, 7 ha of cassava; maximum net profit = ₦2,147,500

C. 8 ha of maize, 4 ha of cassava; maximum net profit = ₦1,852,000

D. 3 ha of maize, 9 ha of cassava; maximum net profit = ₦3,222,000

Correct Answer: A

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Question 12 View Details

The mean monthly temperatures (°C) for a location are: Jan 22, Feb 24, Mar 26, Apr 28, May 30, Jun 28, Jul 27, Aug 27, Sep 26, Oct 24, Nov 23, Dec 22. The mean monthly precipitation (mm) are: Jan 80, Feb 70, Mar 60, Apr 50, May 40, Jun 30, Jul 20, Aug 20, Sep 30, Oct 50, Nov 70, Dec 80. Using the Köppen climate classification, determine the first two letters (climate group and precipitation type) for this location.

A. Af

Correct B. Aw

C. Cw

D. Am

Correct Answer: B

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Question 13 View Details

A soil sample contains 30 % sand, 45 % silt and an unknown percentage of clay. Its bulk density is \(1.4\) g cm\(^{-3}\) and its measured porosity is 48 %. Assuming a particle density of \(2.65\) g cm\(^{-3}\), (a) find the percentage of clay in the sample, and (b) check whether the given bulk density is consistent with the measured porosity using the relation \(\text{porosity}=1-\frac{\text{bulk density}}{\text{particle density}}\).

A. Clay = 30 %; bulk density is consistent (theoretical porosity 49.5 % ≈ measured 48 %).

B. Clay = 25 %; bulk density is inconsistent (theoretical porosity 47.2 % ≠ measured 48 %).

Correct C. Clay = 25 %; bulk density is consistent (theoretical porosity 47.2 % ≈ measured 48 %).

D. Clay = 20 %; bulk density is inconsistent (theoretical porosity 45.0 % ≠ measured 48 %).

Correct Answer: C

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Question 14 View Details

A rock sample consists of 55 % quartz (Mohs hardness 7), 30 % feldspar (hardness 6) and 15 % mica (hardness 2.5) by volume. A geologist scratches the sample with a reference mineral of hardness 5.5 and observes that 40 % of the sample surface is scratched. Assuming the proportion scratched is directly proportional to the volume fraction of minerals softer than the reference, is the observed scratch percentage consistent with the mineral composition? Show your calculation.

Correct A. No; expected scratched proportion is 15 % but 40 % was observed, so the result is inconsistent.

B. Yes; expected scratched proportion is 40 % and 40 % was observed, so the result is consistent.

C. No; expected scratched proportion is 25 % but 40 % was observed, so the result is inconsistent.

D. Yes; expected scratched proportion is 30 % but 40 % was observed, so the result is consistent.

Correct Answer: A

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Question 15 View Details

A field has a soil pH of 5.2. To raise the pH to 6.5, agricultural lime (CaCO\(\_3\)) is applied. The lime requirement (LR) in kg ha\(^{-1}\) is given by \(LR = \frac{(\text{target pH} - \text{current pH}) \times 1000}{\text{buffer pH}}\), where the buffer pH for this soil is 0.5. Because only 80 % of the applied lime is effective, the amount applied must be increased accordingly. Calculate the amount of lime that should be applied per hectare to achieve the target pH.

A. 4,100 kg per hectare

B. 2,600 kg per hectare

Correct C. 3,250 kg per hectare

D. 3,800 kg per hectare

Correct Answer: C

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Question 16 View Details

From the year 2000 the town had a population of 150,000. Between 2000‑2005 the annual growth rate was \(2.5\%\). Between 2005‑2010 it changed to \(1.8\%\) per year. From 2010‑2015 the natural growth rate was \(2\%\) per year but each year \(1,200\) people migrated out of the town. Assuming compound growth each year, what was the population of the town at the end of 2015? Give your answer as the nearest whole number.

A. 198800

B. 201200

Correct C. 199519

D. 197500

Correct Answer: C

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Question 17 View Details

On a topographic map the contour interval is \(20\) m. Point A lies on the \(340\) m contour and point B on the \(420\) m contour. The straight‑line distance between A and B measured on the map is \(3\) cm. The map scale is 1 : 50 000 (\(1\) cm on the map equals \(500\) m on the ground). A road is to be built directly from A to B. What is the length of the road (in metres) to the nearest metre, taking the slope into account?

A. 1512

B. 1500

Correct C. 1502

D. 1496

Correct Answer: C

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Question 18 View Details

Soil in a field has a field capacity of \(0.35\) cm³ cm⁻³ and a wilting point of \(0.15\) cm³ cm⁻³. The effective root depth is \(60\) cm. A crop requires \(5\) mm of water per day for \(10\) days. The soil is initially at field capacity. After the first \(5\) days a rainfall of \(10\) mm uniformly wets the soil. Assuming no other losses, for how many total days can the crop be sustained without further irrigation? Give your answer as a whole number of days.

A. 28

B. 30

Correct C. 26

D. 24

Correct Answer: C

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Question 19 View Details

A town of \(25\,000\) inhabitants is \(45\) km from the nearest city. The normal travel speed on the connecting road is \(60\) km h⁻¹, but the road condition adds an extra \(15\) minutes to the journey. According to NECO criteria a settlement is classified as a "regional centre" if (i) its population is between \(20\,000\) and \(100\,000\) and (ii) the travel time to the nearest city is less than \(1\) hour. Does this town qualify as a regional centre? Answer "Yes" or "No".

A. Maybe

B. Yes

C. Uncertain

Correct D. No

Correct Answer: D

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Question 20 View Details

A manufacturing firm produces widgets. Fixed costs are \(\text{₦}2{,}000{,}000\) per year. Variable cost per widget is \(\text{₦}150\). Each widget sells for \(\text{₦}250\). The government imposes a 10\% sales tax on the revenue, payable by the firm. What is the minimum number of widgets the firm must produce and sell each year to achieve a profit of at least \(\text{₦}500{,}000\) after tax? Give the smallest whole number of widgets.

A. 33500

B. 33333

Correct C. 33334

D. 34000

Correct Answer: C

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Question 21 View Details

A map of a local area is drawn at a scale of \(1:80,000\). On the map the straight‑line distance between Village A and Village B measures \(3.5\) cm. What is the actual distance between the two villages in kilometres?

A. 4.0 km

B. 3.5 km

C. 2.0 km

Correct D. 2.8 km

Correct Answer: D

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Question 22 View Details

A catchment area of \(12\) km\(^2\) receives a uniform rainfall of \(45\) mm over a 24‑hour period. Twenty‑five percent of the rainfall is lost to infiltration and evaporation. The remaining runoff is to be conveyed through a rectangular concrete drainage channel that is \(3\) m wide and \(1.5\) m deep. The channel must carry the runoff in \(6\) hours. Assuming Manning's roughness coefficient \(n = 0.015\) and that the channel flows full during the runoff period, determine the minimum slope (as a percentage) required for the channel.

A. 0.4 % (approximately)

B. 0.6 % (approximately)

C. 0.8 % (approximately)

Correct D. 0.5 % (approximately)

Correct Answer: D

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Question 23 View Details

A rectangular foundation measuring \(4\) m × \(6\) m rests on a clay layer \(5\) m thick. The clay has a compression index \(C_c = 0.25\), initial void ratio \(e_0 = 0.9\) and a pre‑consolidation pressure of \(150\) kPa. The effective stress increase at the centre of the foundation due to the imposed load is \(120\) kPa. The coefficient of consolidation for the clay is \(C_v = 2 \times 10^{-6}\) m\(^2\)/s and drainage occurs only at the base of the layer. (a) Calculate the primary consolidation settlement of the foundation (in mm). (b) Estimate the time required to achieve \(90\%\) consolidation (in days).

A. 150 mm; 110 days

Correct B. 168 mm; 123 days

C. 180 mm; 130 days

D. 165 mm; 100 days

Correct Answer: B

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Question 24 View Details

A map has a scale of \(1\) cm : \(250\) m. On the map the distance between two towns measures \(7.6\) cm. (a) What is the actual distance between the towns in kilometres? (b) If a new road reduces the map distance by \(1.2\) cm, by how many kilometres does the actual distance decrease?

A. 1.9 km; 0.2 km

B. 1.8 km; 0.3 km

Correct C. 1.9 km; 0.3 km

D. 2.0 km; 0.3 km

Correct Answer: C

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Question 25 View Details

A region is situated at an altitude of \(1500\) m. The sea‑level mean temperature is \(26^{\circ}C\) and the environmental lapse rate is \(6.5^{\circ}C\) per 1000 m. The region receives an annual rainfall of \(1100\) mm and experiences a distinct dry season lasting \(5\) months. Using the following vegetation classification:\n\n- Tropical rainforest: rainfall \(>2000\) mm, temperature \(>20^{\circ}C\).\n- Tropical savanna: rainfall \(800\)-\(1500\) mm, temperature \(15\)-\(30^{\circ}C\), dry season \(>4\) months.\n- Subtropical forest: rainfall \(1000\)-\(1500\) mm, temperature \(10\)-\(20^{\circ}C\), no pronounced dry season.\n- Montane grassland: rainfall \(800\)-\(1300\) mm, temperature \(5\)-\(15^{\circ}C\), dry season \(>3\) months.\n\nDetermine the dominant vegetation type of the region.

Correct A. Tropical savanna

B. Montane grassland

C. Subtropical forest

D. Tropical rainforest

Correct Answer: A

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