A car travels from P to Q at a constant Speed ,if its speed were increased by 10km/h ,it would cover taken 1 hour lesser to cover the distance, it would have taken further 45 mints if the speed was further increased by 10 km/h .
The distance between P and Q is...??????
Let speed =x and time =t , distance is constant , (45 minutes=7/4 hour)
DISTANCE =SPEED *TIME = x*y
(x+10)*(t-1) =xt, xt-x+10t-10=xt , -x+10t-10=0 , 10t-x=10 ----i
(x+20)*(t-7/4)=xt , xt-7x/4+20t-35=xt , -7x/4+20t=35 , 20t-7x/4=35 ----ii
Solve i and ii
X=60 , y=7 distance =x*y =60*7 =420km