Ramesh walks at 56th of his usual speed and reaches school 4

Ramesh walks at 5/6th of his usual speed and reaches school 4 minutes late. Find the usual time taken by him to reach school.

Solution

Let x=the time it takes to go to school at the usual speed
5x/6=4
x=4*6/5
=24/5 min. Time it takes to go to school at the usual speed.