Re: Suppose a is a three-digit number that has 3 prime factors and b is a
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07 Apr 2024, 01:36
D.
This number t4eory problem tests your understanding of prime factors and number composition.The first step is to find the smallest 3-digit number which has 3 prime factors. Choose the two smallest possible primes: 2 and 3. Find the smallest prime which, when multiplied with 2 and 3, is a 3-digit number.This happens to be 17: 2(3)(17) = 102.
101 is a prime number, so with 102 you have found the smallest 3-digit number with 3 prime factors. Call this a.
Now find the smallest 2-digit number with 3 prime factors. The three smallest prime factors are 2, 3, and 5:2(3) (5) = 30, which is a 2-digit number. Call this b.
This gives you: ab = (2 • 3 • 17) • (2 • 3 • 5) = 22 • 32 • 5 • 17 = 3060. As you can see, 3060 has exactly 4 prime factors: 2, 3, 5, 17.
The correct answer choice is D.