UPSC CAPF Assistant Commandant Model Paper 1

Formula:
After meeting each other, two trains of speeds x km/hr and y km/hr respectively complete their journeys in t1 and t2 , then
(x/y)‌2=t2 /t1
Calculation:
Let t1 =25 and t2 = 64
Let speed other car be x km/hr respectively,
According to the question
(8/x)‌2 = (64/25)
⇒ 8/x = √64/25
⇒ 8/x = 8/5
⇒ x = 8 × (5/8)
⇒ x = 5 km/hr
∴ Speed of other car was 5 km/hr.