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Difficulty: 2/102025 IOQM 2025 (Q1)

If of a number is , then what is of ?

Options:

  • A.

    42

  • B.

    41

  • 40

  • D.

    43

Guide / Hint

Hint 1: Think about what happens when you swap the percentage and the number. Is of the same as of ?

Hint 2: Write out the expression: of . Compare this with of .

Hint 3: They are identical expressions! of of .

Solution

Step 1: Find from of .

Step 2: Compute of :

Key Insight: Notice that of of . The percentage operation is commutative: of of .

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    2025 IOQM 2025 Q1 - Olympiad Math Olympiad Question | Leminno