A is chasing B in the same interval of time, A jumps 8 times, while B jumps 6 times, But the distance covered by A in 7 jumps is the same as that of B in 5 jumps. The ratio between the speeds of A and B is ________ .

20 : 21

7 jumps of A = 5 jumps of B 

8 jumps of A = \(\frac{5}{7}\) x8 jumps of B 

                   = \(\frac{40}{7}\)  jumps of B 

The required ratio =  \(\frac{40}{7}\)  : 6

                           = 40 : 42 = 20 : 21