Question 2
Let $a,b$ be positive integers. Exactly three of the following four statements are true, and one is false:
a) $a+1$ is divisible by $b$.
b) $a=2b+5$.
c) $a+b$ is a multiple of $3$.
d) $a+7b$ is prime.
Find $a,b$.
a) $a+1$ is divisible by $b$.
b) $a=2b+5$.
c) $a+b$ is a multiple of $3$.
d) $a+7b$ is prime.
Find $a,b$.