Question

N is a multiple of 6 between 20 and 35. It also has three prime factors. What is the prime number closest to N?​

Answer 1

In the numbers from 1 to 100, there are 4 numbers that have exactly 3 factors. The numbers are 4, 9, 25, and 49. As someone else pointed out, these are squares of primes, which makes sense. If a number is any other kind of composite number, it would have at least two factors in addition to 1 and itself.