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If a and b are prime numbers, such that a > b, which of the following cannot be true?

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Re: If a and b are prime numbers, such that a > b, which of the following cannot be true?

by Scott@TargetTestPrep » Sun Dec 06, 2020 8:54 am
BTGModeratorVI wrote: ↑
Thu Dec 03, 2020 2:51 pm
 If a and b are prime numbers, such that a > b, which of the following cannot be true?

A. a+b is prime.
B. ab is odd.
C. a(a-b) is odd.
D. a-b is prime.
E. a^b is even.

Answer: E
Solution:

Recall that all the prime numbers other than 2 are odd. Since a > b, a must be odd, no matter the value of b . Thus, a^b must be odd since any odd number raised to any power is odd. So, a^b can’t be even.

Answer: E

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