Answer:
Let's define the variables:
x = yards of Organza ribbon that you buy.
y = yards of Satin ribbon that you buy.
We know that the price per yard of Organza ribbon is $0.07, this means tat if you buy x yards, the cost will be:
C = x*$0.07
And the cost of the Satin ribbon is $0.04, so if you buy y yards of that ribbon, the cost will be:
C = y*$0.04
Adding that together, the total cost is:
C = x*$0.07 + y*$0.04
Now we know that you pay $5, this means that the total cost is exactly $5, then we have the equation:
$5 = x*$0.07 + y*$0.04
Now we can isolate the variable y to get:
y = ($5/$0.04) - x*($0.07/$0.04)
y = 125 - x*1.75
Now we can just input different values of x to find the correspondent value of y.
This means that:
if x = 0 (0 yards of the Organza ribbon)
then:
y = 125 - 0*1.75 = 0
This combination is:
0 yards of organza, and 125 yards of satin.
Now, if x = 20, then:
y = 125 - 20*1.75 = 90
This combination is:
20 yards of organza, and 90 yards of satin.
if x = 40, then:
y = 125 - 40*1.75 = 55
This combination is:
40 yards of organza, and 55 yards of satin.
The 3 combinations that we found cost exactly $5.
