The number of boys . . . . . B
Twice the number of boys . . . 2B
4 more than twice the number of boys . . . 2B+4
You said that the number of girls is equal to that, so . . . G = 2B+4
But you also told us what G is: 16 = 2B+4
Subtract 4 from each side: 12 = 2B
Divide each side by 2 : 6 = B
There you have it. There are 6 boys in the club.
