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Re: If positive integer m were increased by 20%, decreased by 2
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14 Jun 2018, 04:19
Explanation
If m were increased by 20%, decreased by 25%, and then increased by 60%, it would be multiplied by 1.2, then 0.75, then 1.6.
Since (1.2)(0.75)(1.6) = 1.44, doing these manipulations is the same as increasing by 44%, or taking 144% of a number (this is true regardless of the value of m).
Alternatively, pick a real value for m.
Because this is a percent problem, 100 is a good number to pick. First, 100 is increased by 20%: (100)(1.2) = 120.
Next, 120 is decreased by 25%, which is the same as multiplying by 75%: (120)(0.75) = 90.
Finally, 90 is increased by 60%: (90)(1.6) = 144. The new number is 144 and the starting number was 100, so the new number is\(\frac{144}{100}\) % of the original number, or 144%.