Correct Answer - C
1 hour `rarr (15)/(60)` hour `=(1)/(2)` hour
8 units `- 8 xx (1)/(4) = 2` hr.
Total distance `= 35 xx 2 = 70km`.
Alternate
`rArr` (माना कि कुल दुरी) `= dkm`
According to the question,
`rArr (d)/(35) - (d)/(40) = (15)/(60)`
`rArr 40d - 35 d = (15 xx 40 xx 35)/(60)`
`rArr 5d = 350`
`rArr` Distance = 70km.