Question

After covering a distance of 30km with uniform speed there is some defect in a train engine and therefore it's speed gets reduced to 4/5 of its original speed. Consequently, the train reaches it's destination late by 45 min. If , the defect in engine would have occured after covering 18 km more distance , the train would have reached 9 min earlier . The original speed of the train is​

Answer 1

Answer:

let total distance after 30km be x

let orignal speed be v

after defect be 4v/5

if there was no defect then time taken would have been

$\frac{30 + x}{v}$

orignal time taken is

$\frac{30}{v} + \frac{x}{ \frac{4}{5} v} = 45 + \frac{30 + x}{v}$

this will give 1 eqn in x and v

2nd case

orignal time taken is

$\frac{48}{v} + \frac{x - 18}{ \frac{4}{5} v} = \frac{30 + x}{v} - 9$

-2nd eqn

now there are 2 variables and 2 eqns easily solvable