Question

A body wlaks to his school at a distance of `6 km ` with constant speed of ` 2-5 km h^(-1)` and walks bach with a constant speed of ` 4 km h^(-1)~ What is avetage speed for the round trip in km h^(-1)` ?

Answer 1

Total time in going and coming back,
` T= 6/(2.5) + 6 /4 `,
total distance travelled,
` S = 6 + 6 12 km`,
Average speed ` = S/T =(12)/((2//2 .5 )+ (6 //44))`
`= (40)/(13) km h^(-1)`.