Question

A train travels 180 kilometre per hour at uniform speed if the speed had been 9 kilometre per hour more it would be taken 1 hour less for the same journey find the speed of the train​

Answer 1

Answer:

Let x be the distance

speed is 180km/hr

case 1 : speed =distance /time

therefore time =distance /speed

180/x (eq1)

case2: a.t.q

180/x+9 (eq2)

from 1 and 2

180/x-180/x+9=1

180(x+9)-180x÷x^+9=1

x^+9x-1620=0

by quadratic formula

d=b^-4ac

(9^)-4×1×1620

81+6480

6561

x=-b+-under root d ÷2a

-9+-81÷2

speed =36km/hr