Question 84

A taxi going at 90 km/hr takes 35 minutes to travel a certain distance. By how much should it increase its speed (in km/hr) to travel the same distance in 21 minutes?

Solution

Speed of car = 90 km/hr

Time taken by car = 35 minutes = $$\frac{35}{60}$$ km/hr

=> Distance travelled = speed x time

= $$90\times\frac{35}{60}=52.5$$ km

Thus, speed required to travel the same distance in 21 minutes ($$\frac{21}{60}$$) hr = $$\frac{52.5}{\frac{21}{60}}$$

= $$150$$ km/hr

$$\therefore$$ Increase in speed = $$150-90=60$$ km/hr

=> Ans - (A)