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Problem #72 · October 7, 2026

Divisibility rules

Which of the following numbers is divisible by both 22 and 55?
  1. A45
  2. B52
  3. C70
  4. D85
  5. E96

WORKED EXAMPLE

Solution

For a number to be divisible by 22, it must be even, and for it to be divisible by 55, it must end in 00 or 55. Both conditions hold at the same time only when the number ends in 00. Since the number 7070 ends in 00, it is divisible by both 22 and 55 (that is, by 1010).
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