Stephen says that the numbers 38 and 40 are relatively prime. Explain why he is incorrect in making this statement.

38 and 40 are both even numbers.

even numbers cannot be prime numbers; as they have their own factors.

prime numbers only have two factors: the number 1 and the number itself.

example: 17 is a prime number. the only factors it has is 1 and 17.

38 and 40 are both divisible by 2, so they have more than two factors:

38 = 1 * 38,  2 * 19

40 = 1 * 40, 2 * 20, 4 * 10, 4 * 5

therefore, they are not relatively prime, or prime at all; they are even numbers.

correct answer:

b.(19,-2)