Question

Which are the numbers between 1 and 100 that have exactly three factors?

• A. 49, 16, 64, 81, 100
• B. 1, 4, 9, 25, 36, 49, 16, 64, 81, 100
• C. 4, 9, 25, 49.
• D. 9, 25, 49, 100

Answer 1

The correct option is C

4, 9, 25, 49.

4, 9, 25 and 49.
All these numbers are the squares of prime numbers

Hence their factors are only 1, the square root of the numbers and the number itself.