The cost of fuel in running an engine is proportional to the square of the speed and is Rs
MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation
Problem
The cost of fuel in running an engine is proportional to the square of the speed and is Rs. 48 per hour for a speed of 16 km/hr. Other costs amounts to Rs. 300 per hour. The most economical speed (in km/hr), is
(a) 30
(b) 32
(c) 40
(d) 24