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Problem #12 · August 8, 2026

Divisibility rules

Which of the following numbers is divisible by 2525?
  1. A1035
  2. B2150
  3. C3205
  4. D4520
  5. E5010

WORKED EXAMPLE

Solution

For a number to be divisible by 2525, it must end in 0000, 2525, 5050, or 7575. The number 21502150 ends in 5050, so 2150=25⋅862150 = 25 \cdot 86. The remaining numbers end in 3535, 0505, 2020, and 1010, so they are not divisible by 2525.
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