Could you please share the chart the problem refers to?
We are asked to find an equation that gives the cost (C) of the skirt as a function of the number of yards (y) of material used.
The information given is:
y = 2.5 then C = $15.60
y = 3.5 then C = $21.84
y = 4 then C = $24.96
when the cost is $15.60, the amount of material in yards is 2.5 yards
so let's find the cost per yard as the quotient cost in $ divided by yard of material
Cost/yards = $21.84/3.5 = 6.24 $ per yard
The quotient gives the same value for all the three cases:
$15.60 / 2.5 = $6.24 per yard
$24.96 / 4 = $6.24 per yard
then the cost is going to be given by the equation:
C = 6.24 * y
This is the equation they asked you to find (naming "C" the cost, and "y" the number of yards of material used.
The equation contains ""unknowns"
Recall that the question is:
What is the equation for finding the cost per skirt made from the same material?
So they want a mathematical formula/equation that allows everyone to estimate the cost (C) given the number of yards of mwterial used (y)
So if you give the following equation (called equation because it must contain an "equal" sign):
C = 6.24 * y
A second problem gives you the amount paid for number of pounds of blueberries
The data says:
3 pounds cost $5.4
7 pounds cost $12.6
We proceed as before, and get that the amount per pound is obtained via the quatient: Price (C) divided by number of pounds (p)
C / p = $5.4 / 3 = $1.8 per pound
that gives us the equation:
C = $1.8 * p