Question

18. Which of the following groups of numbers are all prime numbers?

A. 7, 17, 29, 49
B.2, 3, 5, 9
C. 2, 5, 15, 19
D. 3, 11, 23, 31
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Answer 1

D

Explanation:

3,11,23, and 31 can only be divided by 1 without becoming a decimal.