To cover a distance of 832 km a train A takes 2\(\frac{2}{3}\) hours more than train B.  If the speed of A is doubled, it would take 1\(\frac{1}{3}\) hour less than B.  What is the speed (in km/h) of train B?

156

Speed_A =  1    :   2

Time_A    =  2    :   1    (since distance covered is same)

                 l_____l

                    1 → 2\(\frac{2}{3}\) + 1\(\frac{1}{3}\) =\(\frac{8}{3}\) + \(\frac{4}{3}\) =  4

                    1 → 4 hour

When A's speed is double, A takes 4 hours

Therefore ATQ, 

B takes = 4 + 1\(\frac{1}{3}\) = 5\(\frac{1}{3}\) = \(\frac{16}{3}\)

S_B = \(\frac{832 × 3}{16}\) = 156 km/h