Question

In a circular race of 1500 m, P and Q start from the same point and at the same time, at speeds of 20 km/h and 35 km/h, respectively. After what time will they meet for the first time on the track if they are running in the same direction?

• A. 340 sec
• B. 640 sec
• C. 840 sec
• D. 360 sec

Answer 1

Answer:

D. 360 sec

Length of circular track = 1500 m = 1.5 km

Speeds:

• P = 20 km/h

• Q = 35 km/h

Since they run in the same direction, relative speed:

$35-20=15\text{ km/h}$

They will meet when Q gains one full round over P.

Distance to be covered relatively = 1.5 km

Time taken:

$t=\frac{1.5}{15}=0.1\text{ hour}$

Convert into minutes:

$0.1 \times 60 = 6$
They will meet after 6 minutes=360sec.