The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is: Answers:
A) 57.5 km/hr.
B) 77.5 km/hr.
C) 87.5 km/hr.
D) 97.5 km/hr.
E) 37.5 km/hr.
C   87.5 km/hr.   Let the speed of two trains be 7x and 8x km/hr.   Then, 8x = 400/4= 
<gadget id="calculator">400/4</gadget>
<output>100</output>
100   Let the speed of two trains be 7x and 8x km/hr.   --&gt; x= 100/8= 
<gadget id="calculator">100/8</gadget>
<output>25/2 = around 12.5</output>
12.5   --&gt; Speed of first train= (7 x 12.5) km/hr = 87.5 km/hr.
<result>C</result>
The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is: