Question

An express train takes 1h less than the passenger train to travel 132km from Bengaluru to Mysore. If the average speed of the express train is 11km/h more than the passenger train. Find the average speed of the two trains

Answer 1

let the average speed of train be Xkm/h and the speed of exp.train be-(X+11)km/h

time 1-130/X hrs

time 2-132/X+11 hrs

*132/X =132/(X+11)-1/1

132/X-13/(X+11)=1

132(1/X-1/(X+11))=2

1/X-1/X+11=1/132

11/X2+11x=1/132

X2+11x=1452

x2+11x-1452=0

Now,

D=b2-4ac=5929

Now,

x=-b+_underoot b/2a

=-11+_77/2

=-11+77/2 and-11-77/2

=66/2

=33 km/ hr