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SSC CHSL 2024 PYQ — Question 53

SSC CHSL - 01 July 2024 - Shift 1 • Quantitative Aptitude • Q53

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A motorcycle covered the first 60 km of its journey at an average speed of 40 km/h. The speed of the motorcycle for covering the rest of the journey, i.e. 90 km, was 45 km/h. During the whole journey, the overall average speed of the motorcycle was:

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Correct answer: D

Explanation

The correct answer is option 4 i.e. 426742\frac{6}{7}km/h.

The first part of the journey (60 km at 40 km/h).
Time = DistanceSpeed\frac{Distance}{Speed} = 60km40km/h\frac{60 km}{40 km/h} = 1.5 hours.

The second part of the journey (90 km at 45 km/h).
Time = DistanceSpeed\frac{Distance}{Speed} = 90km45km/h\frac{90 km}{45 km/h} = 2 hours.

Total Distance = 60 km + 90 km = 150 km.

Total Time = Time for the first part + Time for the second part = 1.5 hours + 2 hours = 3.5 hours.

Overall Average Speed = Total Distance / Total Time = 150 km / 3.5 hours = 42.857 km/h or 4267\frac{6}{7}​ km/h