Question

Given that $(p+3)$ is the highest common factor of 81 and 108, find the value of $p$.

• A. 6
• B. 12
• C. 9
• D. 24

Answer 1

The correct option is D 24

Prime factors of 81 and 108 are:
81 = 3 $\times$ 3 $\times$ 3 $\times$ 3
108 = 2 $\times$ 2 $\times$ 3 $\times$ 3 $\times$ 3
The common factors are 3 $\times$ 3 $\times$ 3 = 27
$\therefore$ $(24+3)=27;p=24$