The speed of train A is 16 km per hour less than the speed of train B. To cover a distance of 384 km, B takes 4 hrs less time than A. What is the speed (in km/h) of train B?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 48.
Let the speed of train B = x km/hr
Speed of train A = (x - 16) km/hr
Distance covered = 384 km/hr
The time taken is = (Distance/Speed)
To cover a distance of 384 km, B takes 4 hours less than A.
(384/x - 16) - (384/x) = 4
(1/x - 16) - (1/x) = 4/384 = 1/96
x - (x - 16)/x × (x- 16) = 1/96
x(x - 16) = 16 × 96 = 1536
x2 - 16x - 1536 = 0
x2 - 48x + 32x - 1536 = 0
x(x - 48) + 32(x - 48)
x = 48 or x = - 32
Hence, the speed of train B = 48 km/hr.