Answer:
One apple pie is $4 and one blackberry pie is $20
Step-by-step explanation:
Create a system of equations where a is the cost of one apple pie and b is the cost of one blackberry pie:
10a + 2b = 80
10a + 3b = 100
Solve by elimination by multiplying the top equation by -1, then adding the equations together:
-10a - 2b = -80
10a + 3b = 100
Add these together:
b = 20
So, one blackberry pie is $20. Plug in 20 as b into one of the equations, and solve for a:
10a + 2b = 80
10a + 2(20) = 80
10a + 40 = 80
10a = 40
a = 4
So, one apple pie is $4.
One apple pie is $4 and one blackberry pie is $20