Two trains of lengths 100 m and 140 m respectively are running in opposite directions on parallel tracks. If their speed is 29 km/hour and 43 km/hour respectively. In what time will they cross each other?

Two towns P and Q are 170 km apart, a train starts at 9 a.m. from P towards Q at a speed of 40 km/hr, at 11 a.m. another train starts from Q towards P at a speed of 50 km/hr. When will the two trains meet?