Two motorists start together to travel to a certain destination, one at the speed of 4 km/h and the other at the speed of 6 km/h. Find the distance travelled by them (in km) if the motorist travelling at 4 km/h arrives half an hour after the other motorist.

In 1 km linear race, P beats Q by 120 metres or 30 sec. What is the time taken by P to cover the race?

A circular running path is 1452 m in circumference. Two men start from the same point and walk in opposite direction at the speed of 7.5 km/h and 9 km/h, respectively. When will they meet for the first time?

Rajdhani Express train of length 108 m is running at the speed of 128 km/h. Another train of length 148 m is standing at the station. In what time will the Rajdhani Express cross the other train?