Question

An express train takes 1hr less than a passenger train to travel 132km between Mysore and Bangalore. If the average speed of the express train is 11km/h more than that of passenger train, find the average speed of the two trains

Answer 1

ANSWER:

$\small{ \rm{Let \: the \: speed_{avg} \: of \: the \: train \: be \: x \: kmph}}$

$\small{ \rm{Then \: the \: speed_{avg} \: of }} \\ \small{\rm{express \: train \: will \: be = x + 11}}$

Time taken by the passenger train is = 132/x

Time taken by express train = 132/x + 11

We get a quadratic equation like this

→ x² + 11x - 1452 = 0

→ x² + 44x - 33x - 1452 = 0

→ x(x - 33) + 44(x - 33) = 0

→ (x - 33)(x + 44) = 0

→ x = 33 or - 44

Hence, the average speed of passenger train = 33km/h & the average speed of express train = 44km/h