Solving a value mixture problem using a system of linear

We are given that there are 125 boxes. If "x" represents the number of larger boxes and "y" the smaller boxes then this is written mathematically as:
[tex]x+y=125,(1)[/tex]We are also given that the larger boxes weigh 45 pounds and the smaller boxes weigh 30 pounds each and the total weight is 4575 pounds. This is written mathematically as:
[tex]45x+30y=4575,(2)[/tex]We get a system of two equations and two variables. To solve the system we will use the method of elimination. To do that we will multiply equation (1) by -45, we get:
[tex]-45x-45y=-5625[/tex]Now, we add this equation to equation (2):
[tex]-45x-45y+45x+30y=-5625+4575[/tex]Now, we add like terms:
[tex]-15y=-1050[/tex]Now, we divide both sides by -15:
[tex]y=-\frac{1050}{-15}[/tex]Solving the operations:
[tex]y=70[/tex]Now, we substitute the value of "y" in equation (1):
[tex]x+70=125[/tex]Now, we subtract 70 from both sides:
[tex]\begin{gathered} x+70-70=125-70 \\ x=55 \end{gathered}[/tex]Therefore, there are 55 larger boxes and 70 smaller boxes.