A car travels the first `1//3^(rd)` distance at a speed of 30 km/h, the next `1//3^(rd)` distance at a speed of 20 km/h and the last `1//3^(rd)` distance at a speed of 10 km/h. The average speed of the car is

Options

A. 30 m/s
B. `180/11`m/s
C. `50/11 ` m/s
D. none

Answer

B

Explanation

`A.S. (T.D)/(T.T) = (x//3 + x//3 + x//3)/((x)/(3 xx 30) + (x)/(3 xx 20) + x/(3 xx 10))`
`= 180/11`