JAMB Mathematics 1985 Question 16

Question 16

Variation

In a restaurant, the cost of providing a particular type of food is partly constant and partly inversely proportional to the number of people. If the cost per head for 100 people is 30k and the cost for 40 people is 60k, find the cost for 50 people.

A.15k
B.45k
C.20k
D.50k
E.40k

Show the answer and explanation

Answer: D (50k)

Explanation

Cost per head C = a + k/N. 30 = a + k/100 and 60 = a + k/40 give k = 2000 and a = 10. For 50 people: 10 + 2000/50 = 50k.