Question

Brad sold candy bars and cookies for a fundraiser at school. Candy bars sold for $3, and cookies sold for $5. He sold a total of 20 items and made $76. How many candy bars did Brad sell? 12 14 16 18]

Answer 1

Answer: First option

12 candy bars were sold

Step-by-step explanation:

Call x the amount of candy sold and call z the amount of cookies sold. Then we know that

$x + z = 20$

We also know that candy bars sell for $ 3 and cookies sell for $ 5. The profit was $ 76

So:

$3x + 5z = 76$

To find the quantity of candy bars sold we must solve the system of equations:

$x + z = 20\\\\3x + 5z = 76$

Multiply the first equation by -5 and add it to the second equation

$-5x -5z = -100$

               +

$3x + 5z = 76$

--------------------------------

$-2x = -24\\\\x = 12$

Answer 2

Brad sold 12 candy bars.

To find this answer, you could do the following steps.

1. Use the formula $3b + $5c = $76 where "b" is the number of bars and "c" is the number of cookies.

2. Fill in each of the given answers (12, 14, 16, 18) into "b".

3. Subtract the given answers from 20 to get the number of cookies (8, 6, 4, 2).

4. Solve to see if it comes out even.

Below are all the solutions in which you use these steps.

A. $3 * 12 + $5 * 8 = $76

$36 + $40 = $76

$76 = $76

True

B. $3 * 14 + $5 * 6 = $76

$42 + $30 = $76

$72 = $76

False

C. $3 * 16 + $5 * 4 = $76

$48 + $20 = $76

$68 = $76

False

D. $3 * 18 + $5 * 2 = $76

$54 + $10 = $76

$64 = $76

False

Thus making 12 the answer. I hope this helps!