First, let us draw the situation. We have the following:
When resistors are connected in parallel, their resulting resistance can be calculated as:
[tex]\frac{1}{R_t}=\frac{1}{R_1}+...+\frac{1}{R_n}[/tex]
Then, in our case:
[tex]\frac{1}{R_t}=\frac{1}{15}+\frac{1}{15}+\frac{1}{15}=\frac{3}{15}[/tex]
Then, our total resistance is:
[tex]R_t=\frac{15}{3}=5\Omega[/tex]
Our final answer is R=5 Ohms
