Waec Model Questions Vol1 2021 Agricultural Science Question 40

A 5‑ha tomato field is initially affected by Disease X at an incidence of 12 %. If untreated, the incidence rises each month by 8 % of the remaining healthy area. A fungicide applied at the start of a month reduces the current incidence by 70 % and, for that month, prevents any further increase. The fungicide costs ₦8,000 per ha each time it is applied. The market price of tomatoes is ₦150 per kg, the potential yield is 20,000 kg per ha, and each 1 % of disease incidence reduces the yield by 0.5 % of the potential yield. Over a 3‑month period the farmer wishes the **total** loss (profit loss due to disease plus fungicide cost) not to exceed ₦200,000. What is the minimum number of months the farmer must apply the fungicide (starting from month 1) to satisfy this condition?