Hello!
The answer is: 225 hamburgers were sold on Friday.
Why?
Let's make the equations that we need to solve the problem:
Where:
[tex]A=Hamburgers\\B=Cheeseburgers[/tex]
So, if there is a combined total of 387 hamburgers and cheeseburgers,
[tex]A+B=387[/tex]
Also, we know that there were 63 fewer cheeseburgers sold than hamburgers, so:
[tex]B=A-63[/tex]
Substituting B into the first equation, we have:
[tex]A+A-63=387[/tex]
[tex]2A=387+63[/tex]
[tex]2A=450[/tex]
[tex]A=\frac{450}{2}=225[/tex]
So, 225 hamburgers were sold on Friday.
Also, we can calculate how many cheeseburgers were sold:
[tex]B=225-63=162[/tex]
So, 162 cheeseburgers were sold on Friday!
Have a nice day!
