Multiple choice

If a number is decreased by $10$% it becomes $54$. By what per cent should it be increased to make it $72$?

  1. $12$%
  2. $21$%
  3. $10$%
  4. $20$%
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D Correct answer
Explanation

If a number x decreased by 10% is 54, then 0.9x = 54, so x = 60. To increase 60 to 72, the increase is 12. The percentage increase is (12 / 60) * 100 = 20%.

AI explanation

Let the number be x, so x minus 10 percent of x equals 54, which gives 0.90x equals 54 and x equals 60. To make the number 72, the required increase is 72 minus 60, which equals 12. The percentage increase is (12 divided by 60) multiplied by 100, which equals 20 percent.

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