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Question Which of the following numbers is the product of exactly three distinct prime numbers: 45, 60, 91, 105, 330?
45 = 3 × 3 × 5. They are not distinct as it has two 3’s.
60 = 2 × 2 × 3 × 5. They are not distinct as it has two 2’s.
91 = 7 × 13. It has only two distinct prime factors.
105 = 3 × 5 × 7. It has three distinct prime factors 3, 5, and 7.
330 = 2 × 3 × 5 × 11. It has four distinct prime factors.
Thus, only 105 is the product of 3 distinct prime numbers.