Question

SSC Test Questions
A car covers 4 successive 3km stretches at speed of 10kmph, 20kmph, 30kmph & 60kmph resp. Its average speed is ?

Answer 1

Find the time when traveling at a speed of 10 kmph:

Time = Distance ÷ Speed

Time = 3/10  hour

Find the time when traveling at a speed of 20 kmph:

Time = Distance ÷ Speed

Time = 3/20 hour

Find the time when traveling at a speed of 30 kmph:

Time = Distance ÷ Speed

Time = 3/30 = 1/10 hour

Find the time when traveling at a speed of 60 kmph:

Time = Distance ÷ Speed

Time = 3/60 = 1/20 hour

Find the total time:

Total time = 3/10 + 3/20 + 1/10 + 1/20 = 3/5 hour

Find the total distance:

Total distance = 3 x 4 = 12 km

Find the average speed:

Speed = Distance ÷ Time

Speed + 12 ÷ 3/5 = 20 kmph

Answer: 20 kmph