A. Let x = cheese and
y = chocolate
2x + y = 25
x + y = 20
B. Subtract the second equation from the first.
2x + y = 25
-(x + y = 20)
-—————
x = 5
Plug 5 back in to the second equation and solve for y.
x + y = 20
5 + y = 20
Subtract 5 from both sides.
y = 15
5 cheese and 15 chocolate
Used elimination method because coefficients on the y values were both 1 so it was easy to subtract the equations and eliminate the y variable.
1/5=10
There are 10 baseball cards
1/10=5
There are 5 football card's
50-10-5=35
There are 35 basketball card's
35-10=25
Gerry has 25 more basketball card's than baseball card's