A person goes to his office by scooter at the speed of 80 km/hr and reaches 60 minutes earlier. If he goes at the speed 50 km / hr, then he reaches 48 minutes late. What will be the speed of the scooter to reach on the usual time?

Explanation

Given: Speed1 = 80 km/hr Speed2 = 50 km/hr Time difference between the two cases = 60 mins early + 48 mins late = 108 mins = 108/60 hrs Concept: In the equation Time = Distance/Speed, the difference in the times traveled at the two speeds will give the usual time taken to reach the office. Calculation: ⇒ Let the usual time be 'T' hours, and the distance be 'D' kilometers. ⇒ D/80 = T - 1 ⇒ D/50 = T + 48/60 ⇒ Subtracting these two equations we get, ⇒ D/50 - D/80 = 1 + 4/5 ⇒ D = 80 × 3 ⇒ D = 240 km ⇒ Usual time = D/T = 240/80 = T - 1 T = 4hr Usual speed = 240/4 = 60km/hr Hence, the speed of the scooter to reach on the usual time is 60 km/hr.