At a bake sale, as student spent $11.00 buying 3 brownies and 5 cookies. His friend spent $3.95 buying 1 brownie and 2 cookies. What is the price of a brownie?

$2.25

Step-by-step explanation:

Let "b" be the price of 1 brownie and "c" the price of 1 cookie.

At a bake sale, a student spent $11.00 buying 3 brownies and 5 cookies. Symbolicaly,

3 b + 5 c = 11.00   [1]

His friend spent $3.95 buying 1 brownie and 2 cookies. Symbolicaly,

1 b + 2 c = 3.95

b = 3.95 - 2c   [2]

If we replace [2] in [1], we get

3 (3.95 - 2c) + 5 c = 11.00

11.85 - 6c + 5c = 11.00

c = 0.85

If we replace c = 0.85 in [2], we get

b = 3.95 - 2 (0.85) = 2.25