WAEC 2010 Mathematics · Question 2

A car uses one litre of petrol for every 14km. If one of petrol cost N63.00, how far can the car go with N900.00 worth of petrol?

Options

A.420km
B.405km
C.210km
D.200km

Answer: D. 200km

Explanation written with AI and checked against the answer key

Analyze the question: The car covers 14 km per litre. One litre costs N63. We need the distance covered with N900 worth of petrol. Concept: Distance = (number of litres) × (km per litre), where litres = money ÷ price per litre. Solution: Step 1: Litres bought with N900 900 ÷ 63 = 14.2857... litres (that is 100/7 litres) Step 2: Distance Distance = (100/7) × 14 = 100 × 2 = 200 km Check: Cost per km = 63 ÷ 14 = N4.50. So N900 ÷ N4.50 = 200 km. ✓ Answer: The distance is 200 km, which is option D. Tip: When the numbers look awkward (900 ÷ 63), do not divide first. Multiply and simplify as a fraction, or find the cost per km (63/14 = 4.5), which gives a clean calculation. Also, 14 and 63 share a factor of 7, which is a hint that things will simplify.

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