Waec Model Questions Vol1 2025 Economics Question 11

A farmer grows maize on a one‑hectare plot. The input costs are: fertilizer (NPK) at ₦150 per kg and seed at ₦200 per kg. The farmer applies a whole‑number amount of fertilizer F (kg) between 15 kg and 25 kg inclusive. The seed quantity is always 0.25 × F kg. Fixed costs (land, labour, etc.) are ₦30,000 per hectare. The base yield is 2.5 tonnes per hectare. For each kilogram of fertilizer above 15 kg, yield rises by 0.05 tonnes, but the yield cannot exceed 3.0 tonnes. The market price of maize is ₦40,000 per tonne; however, if the total output of the five identical farmers in the region exceeds 13 tonnes, the price falls by 10 % (to ₦36,000 per tonne). Determine the amount of fertilizer (in kg) that each farmer should apply to maximise profit per hectare.