Question

If a scooterist drives at the rate of 25 km per hour, he reaches his destination 7 minutes late, and if he drives at the rate of 30 km per hour, he reaches his destination 5 minutes earlier. How far is his destination?

Answer 1

Assume that he starts travelling to his destination at the same time every day

Let the distance between his destination place and source be 'd'

Let the actual time be 'x'

Distance = Speed × Time

Convert minutes into seconds as the units should be in kmph

As 25 kmph speed resulted in 7 minutes late, it is taken as increment

d = 25(x + 7/60) ---------------(1)

As 30 kmph speed resulted in 5 minutes early, it is taken as decrement
d = 30(x - 5/60) ----------------(2)

(1) and (2) are equal

=> 25(x + 7/60) = 30(x - 5/60)

=> 25x+(25×7)/60 = 30x-(30×5)/60

=> 25x+35/12 = 30x-5/2

=> 30x - 25x = (35/12) + (5/2)
= 65/12

=> 5x = 65/12

=> x = (65/12)/5
= (65/12) × (1/5)
x = 13/12
Substitute the value of x in (1)
=> d = 25(13/12 + 7/60)
=> d = 25(6/5)
=> d = 30km

The required answer is 30 km

hope you understand the solution
:)