Question

Two vehicles start from places P and Q towards Q and P respectively at the same time. After crossing each
other, they complete their journey in 7/2 hours and 18/7 hours respectively. If the second vehicle moves at a
speed of 70 km/h, then find the speed of the first vehicle.
A)54 km/h
B)48.6 km/h
C)72 km/h
D)60 km/h​

Answer 1

Second vehicle will move with speed of 72km/h.

Answer 2

Answer:D)60 km/h

Step-by-step explanation:

Given

let P travels x km and Q travels y km for time t

thus

$t=\frac{x}{v_p}=\frac{y}{70}$----1

Also they travel remaining distance in time $\frac{7}{2}+\frac{18}{7}$

thus

$\frac{x}{70}=\frac{18}{7}$

x=180 km

for y

$\frac{y}{v_p}=\frac{7}{2}$

Substitute y in 1 to get $v_p$

$\frac{180}{v_p}=\frac{v_p\times 7}{2\times 70}$

$v_p=60 km/h$