Question

Which of the sets shown includes the elements of Set Z that are both odd numbers and multiples of 5? (B IS NOT CORRECT)

Z = {−15, −12, −10, 2, 7, 10, 20}


A. {-15}

B {-15, −10, 10, 20}

C. {-15, −10, 7, 10, 20}
D. {−15, −12, −10, 2, 7, 10, 20}

Answer 1

a. {-15}

Explanation:

Given set Z = {−15, −12, −10, 2, 7, 10, 20}, the odd numbers here are -15, and 7. If we divide both numbers by 2 respectively, we would always have a remainder. Therefore, they are both off numbers.

Between -15 and 7, which can we say is a multiple of 5? Definitely, it's -15. Because 5*3 = 15. There is no integer we can multiply by 5 that will give us 7.

Therefore, the set {-15} includes element of set Z that is both an odd number and a multiple of 5.