Ques:- If a 200 m long train crosses a platform of the same length as that of the train in 20 seconds, then the speed of the train is
A. 50 km/hr
B. 60 km/hr
C. 70 km/hr
D. 72 km/hr
Ques:- There is a leak in the bottom of a cistern. When the cisternis thoroughly repaired, it would be filled in 3 ? hours. It now takes half an hour longer. If the cistern is full, howlong will the leak take to empty the cistern?
A. 24 hours
B. 28 hours
C. 21 hours
D. 27 hours
E. None of these