A bullet train covers a distance in 50 min, if it runs at a speed of 48kmph on an average. The speed at which the bullet train must run to reduce the time of journey to 40min will be.  Choose the most appropriate option:	A) 80 kmph	B) 40 kmph	C) 60 kmph	D) 90 kmph	E) 30 kmph

Rationale: c 60 kmph time = 50 / 60 hr = 5 / 6 hr speed = 48 mph distance = s * t = 48 * 5 / 6 = 40 km time = 40 / 60 hr = 2 / 3 hr new speed = 40 * 3 / 2 kmph = 60 kmph
Answer: C