Question

If a man had walk 20 km/hr faster he would have save 1hr in the distance of 600km. find his original speed

Answer 1

If normal speed = x km/h
Then current speed = x+20 km/h
Save time = 1h
Total distance = 600km
600. 600
—— - —— = 1
X. (X+20)

X²+20x =600x+12000-600x
X²+20x= 12000
X²+20x-12000=0
X²+120x-100x-12000=0
X(x+120)-100(x+120)=0
(X-100),(x+120)=0
X=100, x= -120
Then x=100km/h
Normal speed =100km/h