Question

You buy 3 bags of sand and 5 bags of pea gravel for $26. In a second purchase (at the same prices), you buy 4 bags of sand for $8. Let z represent the price in dollars) per bag of sand

and let y represent the price in dollars) per bag of pea gravel Use a graph to find the price per bag of sand and the price per bag of pea gravel
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Answer 1

2z and 4y

Explanation:

We first have to use the second purchase to figure this out, if 4 bags of sand is $8. We have to divide 8 by 4, which we get $2. We use this to find the bags of pea gravel. Since you bought 3 bags, 3 times 2 is 6. We subtract 6 from 26 leading to 20 dollars. We also buy 5 bags of pea gravel so we have two numbers, 20 and 5. We divide 20 and 5 and we get 4 dollars for 1 bag of pea gravel.

Answer 2

Sand = $3/bag; gravel = $4/bag

Explanation:

x = price per bag of sand

y = price per bag of gravel

(1) 4x + 3y = 24

(2) 2x = 6 Subtract 4x from Equation (1)

3y = 24 – 4x Divide each side by 3

(3) y = 8 – (4/3)x Divide each side of Equation (2) by 2

(4) x = 3

Plot a few points for each graph .

Table for Eqn (3)

x y x y

0 8 3 0

3 4 3 2

6 0 3 4

9 -4 3 6

Equation (3) is the red line in the graph below.

Equation (4) is the blue line.

The two lines cross at x = 3, y = 4.

The price of sand is $3/bag.

The price of gravel is $4/bag.

Theres an example! Hope this helps!