For party decorations, you buy 6 rolls of crepe paper and 20 balloons for $11.90. after you start decorating, you determine that you need more party decorations. you buy 2 more rolls of crepe paper and 15 more balloons for $6.05. how much did each roll of crepe paper cost?

Find out the  how much did each roll of crepe paper cost .

To prove

Let us assume that the cost of the  roll of crepe paper be x.

Let us assume that the cost of the balloon be y .

As given

For party decorations, you buy 6 rolls of crepe paper and 20 balloons for $11.90.

Than the equation becomes

6x + 20y = 11.90

As given

After you start decorating, you determine that you need more party decorations.

You buy 2 more rolls of crepe paper and 15 more balloons for $6.05.

Than the equation becomes

2x + 15y = 6.05

Than two equations are

6x + 20y = 11.90 and 2x + 15y = 6.05

Multiply 2x + 15y = 6.05 by 3 and subracted with 6x + 20y = 11.90

6x - 6x + 45y -20y = 18.15 - 11.90

25y = 6.25

y = $0.25

Put in the equation 2x + 15y = 6.05

2x + 15 × 0.25 = 6.05

2x = 6.05 - 3.75

2x = 2.3

x = $1.15

Therefore the each roll of crepe paper cost is  $1.15 .

step-by-step explanation:

the answer is 128

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15