Answer this pleaseeee

Question

A piece of wood is cut into three pieces. The second piece is two times as long as the first piece. The third piece is seven times as long as the first piece. If the piece of wood was 40 inches long before it was cut, how long is the longest piece of wood? 

Answer 1

S=2F, T=7F, F+S+T=40

F+2F + 7F = 40

10F = 40

F =4

S=2F = 8

T=7F = 28