Let
be the weight of i-th player.
1. If the mean weight of 4 backfield members on the football team is 221 lb, then
![(x_1+x_2+x_3+x_4)/(4)=221\ lb.](https://img.qammunity.org/2019/formulas/mathematics/high-school/pit7sre08raub7h937ngew3vya54b7gu1w.png)
2. If the mean weight of the 7 other players is 202 lb, then
![(x_5+x_6+x_7+x_8+x_9+x_(10)+x_(11))/(7)=202\ lb.](https://img.qammunity.org/2019/formulas/mathematics/high-school/hy675cfza0yyf4vkcwxph2lmiq51gkl025.png)
3. From the previous statements you have that
![x_1+x_2+x_3+x_4=221\cdot 4=884 \lb,\\ \\x_5+x_6+x_7+x_8+x_9+x_(10)+x_(11)=202\cdot 7=1414\ lb.](https://img.qammunity.org/2019/formulas/mathematics/high-school/79288mrfvqg2y75n7egjux14l6xyrlf4zf.png)
Add these two equalities and then divide by 11:
![x_1+x_2+x_3+x_4+x_5+x_6+x_7+x_8+x_9+x_(10)+x_(11)=884+1414=2298\ lb,\\ \\(x_1+x_2+x_3+x_4+x_5+x_6+x_7+x_8+x_9+x_(10)+x_(11))/(11)=(2298)/(11)=208(10)/(11)\ lb.](https://img.qammunity.org/2019/formulas/mathematics/high-school/mgb4ws0wgozss4x6mrn5ecgbm63zqpi17u.png)
Answer: the mean weight of the 11-person team is
![208(10)/(11)\ lb.](https://img.qammunity.org/2019/formulas/mathematics/high-school/beirs6k7w99yvvfakpylulny9g76p2q8f3.png)