Answer:
$2.25 is the cost of a brownie
Explanation:
The key to this equation is a elimination.
Give brownie the variable b.
Give cookies the variable c.
3b + 5c = 11.00
1b + 2c = 3.95
Multiple the entire bottom by -3 as to be able to get rid of one variable.
3b + 5c = 11.00
-3b - 6c = -11.85
Now add the top and bottom. This leaves -1c = -0.85 and then divide both sides by -1 to have the numbers become positive. So 1c = 0.85. Therefore, one cookie is $0.85.
Now we can take any of those equations and substitute c with 0.85.
1b + 2(0.85) = 3.95
1b + 1.7 = 3.95
Subtract 1.7 from 3.95 and get 2.25.
That leaves 1b = 2.25. So 1 brownie is $2.25