IBPS RRB Office Assistant Mains 20 Oct 2019 Paper

The speed of train A and train B is 93 km/hr and 51 km/hr, respectively. When both the trains are running in the opposite direction, they cross each other in 18 seconds. The length of train B is half of the length of train A. If train A crosses a bridge in 42 seconds, then find the length of the bridge.