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What is the least number to be subtracted from 11, 15, 21 and 30 each so that resultant numbers become proportional?
- A1
- B2
- C3
- D4
Correct answer: C
Discussion 1
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CCommunity
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Let the least number to be subtracted be x, then 11 - x, 15 - x, 21 - x and 30 - x are in proportion.
<=> (11 - x) : (15 - x) = (21 - x) : (30 - x)
=> (11 - x)(30 - x) = (15 - x)(21 - x)
From the options, when x = 3
=> 8 * 27 = 12 * 18
Let the least number to be subtracted be x, then 11 - x, 15 - x, 21 - x and 30 - x are in proportion.
<=> (11 - x) : (15 - x) = (21 - x) : (30 - x)
=> (11 - x)(30 - x) = (15 - x)(21 - x)
From the options, when x = 3
=> 8 * 27 = 12 * 18