The speed differential between two trains is 7:8. If the second train travels 400 kilometres in four hours, the first train's speed is:
A. 70 km/hr
B. 75 km/hr
C. 84 km/hr
D. 87.5 km/hr
Answer:D
The speed differential between two trains is 7:8. If the second train travels 400 kilometres in four hours, the first train's speed is:
A. 70 km/hr B. 75 km/hr C. 84 km/hr D. 87.5 km/hr
Explanation: Allow two trains to travel at speeds of 7x and 8x km/hr.After that, 8x = 400 /4 = 100.x = 100 /8 = 12.5 x = 100 /8 =First train speed = (7 x 12.5) km/hr = 87.5 km/hr.