DRDO Multi tasking staff Model paper 8

Let the length of mini-van be ‘N’ m and the speed of the van be ‘A’ km/h
A mini-van crosses people walking at the speed of 4.8 km/h in the same direction as that in which the mini-van is heading in 4.5,
⇒ N/(A - 4.8) = 1/800
⇒ 800N = A - 4.8 ----1
A mini-van crosses two people walking at the speed of 6 km/h in the same direction as that in which the mini-van is heading in 9 s,
⇒ N/(A - 6) = 1/400
⇒ 400N = A - 6 ----2
Solving equation 1 and 2,
⇒ 400N = 1.2 km
⇒ N = 3 m
∴ The length of the mini-van is 3 m.