Question

7. The speed of one car is 20% less than the speed of a second car. What per cent more time does the first car need to travel the same route as the second car?

Answer 1

25% or more

Explanation:

t1 = d1/v1 , t2 = d2/v2.

d1 = d2 , and v1 = 0.8 v2

t1 / t2 = d1/d2 x v2/v1 = v2/v1 ( as d1 = d2 )

t1/t2 = v2 / v1 = v2/0.8 v2 = 1/0.8 = 1.25