Three runners A, B and C run a race , with runner A finished 12 m ahead of runner B and 18 m ahead of runner C , in another same race runner B finished 8 m ahead of runner C . Each runner travels the entire distance at a constant speed . The length of the race is .

48 m

Let A finish the race of = x meter

B finish the race of = x - 12

C finish the race of =  x- 18 ..... (i)

In another race of B & C 

B finish race of = x meter

C finish race of = x - 8  ..... (ii)

Ratio of speeds of B & C

\(\frac{x\;-\;12}{x\;-\;18}\)   =   \(\frac{x}{x\;-\;8}\) 

( x - 12 ) × ( x - 8 ) =  x( x - 18 ) 

on solving , 

 96 = 2x 

x = 48