SSC CPO 2022 PYQ — Question 134

The correct answer is option 2 i.e. 63.2 km/h

We are given that:-

A car travels with a speed of 21 m/sec in the first 10 minutes, 9.0 km in the next 10 minutes and 10 km in the last 10 minutes of its journey.

We have to find The Average speed of the car.

We know that

Average Speed = ${Total Distance}\over {Total Time}$

Thus Total Distance in Km is

⇒ In first 10 minutes, Car is moving at speed of 21 m/s.

We know

Speed =  Distance/Time

Thus,

Distance = Speed × Time

Thus,

Distance = 21 × 60 (10)

Distance = 12600 m

Thus, the Distance in Km in the first 10 minutes is 12.6 km

⇒ In further second and third 10 minutes, the car traveled 9 km and 10 km respectively.

Thus Total Distance = 12.6 + 9 + 10 = 31.6 km

⇒ Total Time in Hours = 10 min + 10 min + 10 min = 30 min = 0.5 Hours

⇒ Thus, Average Speed = 31.6 km / 0.5 hrs

The average speed is 63.2 km/hr