You arrive at your school 5 minutes late if you walk with a speed of 4 km/h, but you arrive 10 minutes before the schedule time if you walk with a speed of 5 km/h. The distance of your school from your house (in km) is :

Options

A. 4
B. 5
C. 10
D. 2

Answer

B

Explanation

`(x)/(4) -(x)/(5) = (15)/(60) = (1)/(4)`
`implies ( 5x - 4x)/(20) = (1)/(4)`
`implies x = (20)/(4) = 5 km`