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SSC GD 2023 PYQ — Question 44

SSC GD Constable (English) - 24 Jan 2023 - Shift 3 • Quantitative Aptitude • Q44

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A and B can finish a work in 15 days and 10 days, respectively. A started the work alone and after 5 days, B joined A in the work. They both did the remaining work. What is the total number of days to complete the work?

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 9 days

Concept USed:

Total work = Efficiency × Time

Explanation:

According to the given question,

Let the total work done be LCM(15, 10) = 30 units

Now, Efficiency of A = 301530 \over 15 = 2 units/day

And efficiency of B = 301030 \over 10 = 3 units/day

Now, A alone worked for 5 days, Total work completed by A in 5 days = 5 × 2 = 10 units

Remainoing work to be completed = 30 - 10 = 20 units

Now, the work done by A and B together in 20(2+3)20 \over (2 +3) = 4 days

So the total number of days required to complete the total work is (5 + 4) = 9 days.

Hence the required answer is 9 days.