Train A takes $1\frac{4}{5}$h more than the time taken by train B to cover a distance of 360 km. If the speed of train A doubles, it will take 36 min less than the time taken by train B to travel the same distance. What is the speed (in km/h ) of train B?

120

1\(\frac{4}{5}\) hours = \(\frac{9}{5}\) hours = 108 minutes

Ratio of  ,         Initial    :     Final

Speed                    1     :       2

Time                       2     :      1

Total time gap Between initial and final = 108 + 36 = 144 mins 

( 2 - 1 )R = 144 min

1R = 144 minutes

Initial Time taken by A = 2R = 288 minutes

According to question ,

288  = 108 + B

B = 180 min  = 3 hours

Speed of B = \(\frac{360}{3}\) = 120 km/h