Usha particpated in a marathon walk and completes the journey in 10 h. if she travels half the distance with a speed of `10 km h^(-1)` and rest of the distance with the speed of `15 km h^(-1)` then calculate the total distance of the marathon walk.

Explanation

Let the total distance be x km.
Spped = `("distance")/("time")`
Time = `("distance")/("speed")`
`t_(1)=x/(2xx10)=x/20`
`t_(2)=x/(2xx15)=x/30,t_(1)+t_(2)` = 10 hours
`x/20+x/30=10`
`50x=6000,x=120km`