Two numbers are in the ratio 3 : 5. If 10 is added to each, the ratio becomes 5 : 7. What is the smaller number?

A. 15

B. 20

C. 25

D. 10

Doubtly AI Asked 27 Oct 2026 AI-generated · not yet verified ssc cgl Save WhatsApp Report

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Answer: A. 15

Answer: (A) 15

Let the numbers be 3k and 5k. Then 7(3k + 10) = 5(5k + 10), so 21k + 70 = 25k + 50 and k = 5.

Smaller number = 3 × 5 = 15.

Shortcut: adding the same number keeps the difference fixed. Both ratios have a difference of 2 parts, so the parts are the same size. 3 parts became 5 parts, so 2 parts = 10 and 1 part = 5. Smaller number = 3 × 5 = 15.

Doubtly AI · 27 Oct 2026 AI-generated · not yet verified Report

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Two numbers are in the ratio 3 : 5. If 10 is added to each, the ratio becomes 5 : 7. What is the smaller number?

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