Question
A car travels at three-fourths of
its original speed, taking 20 minutes more than the usual time to cover a given distance. Find the usual time the car takes to cover this distance.Solution
ATQ,
Let the usual speed of the car be '4s' km/h and the distance be 'd' km. Let the usual time taken by the car be 't' hours. Using the relation: 
Now, at three-fourths of the original speed, the speed becomes (3/4) × 4s = 3s The time taken at this speed: 
Substitute 'd' from equation (I):
Multiply both sides by 3: 4t = 3t+1 t = 1 So, the usual time taken by the car is 1 hour or 60 mins
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