SOLUTION
Let the weight of the large box be x
Let the weight of the small box be y
Since the combined weight of the boxes is 90 it follows:
![x+y=90----1](https://img.qammunity.org/2023/formulas/mathematics/college/sgennq9q5a78luygvs462k47zso3s6i8sy.png)
The number of small boxes are 65 and the number of large boxes are 70 and the combined total pounds is 6025
This gives
![65x+70y=6025------2](https://img.qammunity.org/2023/formulas/mathematics/college/j46u2oiab73ngtmugwy0tux8hrox0djbq7.png)
Solve the equation
Frrom equation 1
![y=90-x------3](https://img.qammunity.org/2023/formulas/mathematics/college/yhv0n83vzg374v91g36po80trjayevelqb.png)
Substitute y=90-x into equation 2
This gives
![65x+70\left(90-x\right)=6025](https://img.qammunity.org/2023/formulas/mathematics/college/pqjd8obcbea8zh6fh3mxmlqp0lign3j7vz.png)
Solve the equation
![\begin{gathered} 65x+6300-70x=6025 \\ -10x=6025-6300 \\ -5x=-275 \\ x=(-275)/(-5) \\ x=55 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/c9mez8iewos455itaj9u7zm2me43x0xgh6.png)
Substitute x=55 into equation 3
![y=90-55](https://img.qammunity.org/2023/formulas/mathematics/college/99spsbbmcnv80lh8uqqmp00ly3yyvclm8t.png)
Calculate the value
![y=35](https://img.qammunity.org/2023/formulas/mathematics/college/la6enyupfy5k55brwpoamf1d2y1eh3k364.png)
Therefore the weight of the large box is 55
The weight of the small box is 35