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2016 Math Kangaroo

Problem 10

Problem 10 · 2016 Math Kangaroo Medium
Arithmetic & Operations careful-counting

Together, Paul and Josef are 12 years old. How old will they both be together in four years’ time?

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Answer: E — 20
Show hints
Hint 1 of 2
You don't need each boy's age — only their combined age.
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Hint 2 of 2
In four years, both ages grow, so the total grows by 4 twice.
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Approach: track the combined age
  1. Together they are 12 now.
  2. In four years each is 4 years older, so their combined age rises by 4 + 4 = 8.
  3. Together they will be 12 + 8 = 20.
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