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2018 Math Kangaroo

Problem 9

Problem 9 · 2018 Math Kangaroo Hard
Fractions, Decimals & Percents percent-multiplier

How big is the sum of 25% of 2018 and 2018% of 25?

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Answer: A — 1009
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Hint 1 of 2
A percent “of” is a product, and multiplication can be taken in either order.
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Hint 2 of 2
25% of 2018 and 2018% of 25 are the same number.
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Approach: the two products are equal, so just double one
  1. “25% of 2018” and “2018% of 25” are both \(\frac{25\times 2018}{100}\), so they are equal.
  2. Each equals \(\frac{25\times 2018}{100} = \frac{2018}{4} = 504.5\).
  3. Their sum is \(2\times 504.5 = \) 1009.
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