The ratio between the speeds of two trains is 3 : 7, if the first train runs 240 kms. in 5h, then the difference between the speeds (in kms/h) of both the trains is:

64

Speed of first train = \(\frac{240}{5}\) = 48 km/h

              I^st          :           II^nd  

              3             :           7

According to question, 

3R = 48 km/h

1R = 16 km/h

Difference in speeds of both of the trains = (7 - 3) = 4 R

= 4 × 16 = 64  km/h