A and B together can do a piece of work in 12 days. B and C together in 15 days. C and A together in 20 days. How long will A alone take to do the work? MCQ with Answer and Explanation

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A and B together can do a piece of work in 12 days. B and C together in 15 days. C and A together in 20 days. How long will A alone take to do the work?

A. 20 days

B. 60 days

C. 30 days

D. 40 days

Answer: Option C

Solution (By JKExamLibrary)

2(A+B+C) = 1/12 + 1/15 + 1/20 = (5+4+3)/60 = 12/60 = 1/5 → A+B+C = 1/10. A's work = (A+B+C) - (B+C) = 1/10 - 1/15 = (3-2)/30 = 1/30. So A takes 30 days.

This question belongs to: Maths Percentage

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A machine depreciates 12% per year. Its value after 1 year if purchased for Rs. 60,000 is:

A. 52,000

B. 52,800

C. 53,000

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Correct Answer: Option B

Explanation:
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Question #2

A number increased by 30% then decreased by 30% results in net change of:

A. 9% decrease

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Correct Answer: Option A

Explanation:
1.3 × 0.7 = 0.91, 9% decrease.

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Question #3

A trader bought articles for Rs. 1500. Five were damaged, rest sold at Rs. 3 more than CP each, total profit Rs. 75. Number of articles:

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Correct Answer: Option B

Explanation:
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