Question

If speed of a car increases 10km/hr then time decreases 36 minutes to reach distance of 72 km find the initial speed of the car

Answer 1

u= x km/h

t= x/72 hrs

new speed of car is = (x+10)

new time to cover 72 km/h = 72/x+10

Given: time is reduced by 36 min

72/x - 72/x+10= 36/60

x= -40  /  x= 30

speed can't be negative

therefore initial speed is = 30km/h

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