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UKMT Grey Kangaroo, 2023

Algebra Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

There were twice as many children as adults sitting round a table. The age of each person at the table was a positive integer greater than 1. The sum of the ages of the adults was 156. The mean age of the children was 80% less than the mean age of the whole group. What the sum of the ages of the children?

(A) $10$ (B) $12$ (C) $18$ (D) $24$ (E) $27$

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