Question

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?

Answer 1

Answer:

$$2.25$

Step-by-step explanation:

Let $b =$ the cost of one brownie, $c =$ cost of one cookie

$3b + 5c = 11$

$b+2c = 3.95$

Times $3$ on both sides on the second equation above to get the following:

$3b + 6c = 11.85$

$3b+6c - (3b+5c) = 11.85-11$

$3b+6c-3b-5c = 0.85$

$c = 0.85$

To find the value of $b$, use substitution:

$b+2c = 3.95$

$b = 3.95-2c$

$= 3.95 - 2\times0.85$

$= 2.25$

$\therefore$ the cost of a brownie is $$2.25$

Hope this helps :)