Quadratic equations

let the length of train is y and speed is x m/s. for the first person  relative speed is x - 5/9    ( 2 km/hr = 2*5/18 m/s)                                     so  ( x - 5/9) 9 = y  ==> 9x - 5 = y..(1)    

for second person relative speed is x - 10/9 so  (x - 10/9).10 =  y  =====> 10x - 100/9   =  y.....(2)

by solving we get  x = 55/9 m/s  =  22 km/hr   and y = 50 m