To find out how many members in the club are boys, we can calculate 30% of the total number of members, which is 50.
We find 30% of 50 using the formula:
\[ \text{Number of boys} = 0.30 \times 50 \]
Calculating that:
\[ 0.30 \times 50 = 15 \]
So, there are 15 boys in the club. The answer is:
B. 15