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IMAS 2022 — Upper Primary Grades 5–6 — Round 1 Question 10

IMAS · IMAS 2022 — Upper Primary Grades 5–6 — Round 1

Question 10

In each turn, Alice and Bob alternately picks and crosses out one number from the set: 5, 6, 8, 14, 21, 25, 35, 37 and 63, where Alice goes first. After four turns, the sum of numbers removed by Bob is four times the sum of numbers removed by Alice. What is the remaining number?
  1. 8
  2. 14
  3. 21
  4. 25
  5. 37