Maximum number of juniors on a football team

Question

For a certain football game the coach wants to start one sophomore and at least twice as many seniors as sophomores and juniors combined. What is the maximum number of juniors he can start? Players needed to start a game is at most 11.... Answer is 2 junior players... but I can't figure out how?

I tried using:

     x = juniors, and 
2(x+1) = juniors & sophomores combined,
with 1 sophomore to start with,

but when i solved it with equating it like:

juniors + seniors + sophomores = 11 

like

x + 2(x+1) + 1 = 11 

I got answer x = 8/3, which was not correct.

Answer 1

The constraints are $$o+s+j\le 11\\ s=1\\ o \ge 2(s+j)$$ Where $o$ are seniors, $s$ sophomores and $j$ juniors starting. Now if $j\ge3$, $o \ge 2\cdot(3+1) = 8$ so $o+s+j\ge12 > 11$ wich is impossible. If $j=2$, $o \ge 6$ wich is okay because $6+1+2 = 9 \le 11$. He'd send $2$ juniors, $1$ sophomore and $8$ seniors.