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SSC Selection Post 2020 PYQ — Question 70

SSC Selection Post - Matriculation Level 2020 - 14 Nov 2020 - Shift 1 • Quantitative Aptitude • Q70

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A person travelled the first half of the distance from her house to her office at 24 km/h, exactly half of the remaining distance at 20 km/h, and the rest at 15 km/h. Her average speed (km/h) in the entire journey was:

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 20.

Let total distance = 2D

According to the question,

⇒ D24+D40+D30{D\over24}+{D\over40}+{D\over30} = 5D+3D+4D1205D+3D+4D\over120 = 12D12012D\over120 = D10D\over10

Average speed = 2DD102D\over{D\over10} = 20 km/hr