A bus covers the first 10 km of its journey at an average speed of 40 km/hr and the remaining 45 km at an average speed of the bus for its total journey is

Options

A. `52.5` km/h
B. 55 km/h
C. 50 km/h
D. `57.5` km/h

Answer

B

Explanation

Time taken by the bus to cover 10 km ,
`t_(1) =10/40 = 1/4 h `
Time taken by the bus to cover remaining 45 km ,
`t_(2) = 45/60 = 3/4 h `
Average speed = `("Total distance covered ")/("Total time"(t_(1)+t_(2)))`
`=(10+45)/((1/4+3/4))= 55 km//h` .