Question 153084: For a school play, 340 tickets with a total value of $810 were sold. Some tickets cost $2 and some cost $3. How many of each type were sold? Answer by jim_thompson5910(35256) (Show Source):
First translate the word problem into the system of equations:
Let's use substitution to solve the system
Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to solve for y.
So let's isolate y in the first equation
Start with the first equation
Subtract from both sides
Rearrange the equation
---------------------
Since , we can now replace each in the second equation with to solve for
Plug in into the first equation. In other words, replace each with . Notice we've eliminated the variables. So we now have a simple equation with one unknown.