A car moves a distance of `200 m`. It covers the first-half of the distance at speed `40km//h` and the second-half of distance at speed `v km//h`. The average speed is `48km//h`. Find the value of v.

Options

A. `56` km/hour
B. `60` km/hour
C. `50` km/hour
D. `48` km/hour

Answer

B

Explanation

`ltVgt = ("Total distance")/("Total time")`
`V_(1)=48=(2km)/((1)/(40)+(1)/(V))`
`implies48=(2xx40V)/(V+40)`
`impliesV+40=(80)/(48)V`
`implies24V+960=40V`
`implies 16V=960`
`V=60` km/hr