Answer: 6 pounds of sugar candy, and 9 pounds of chocolate candy.
Step-by-step explanation:
Let's define the variables:
C = pounds of chocolate candies used.
S = pounds of sugar candies used.
We know that he wants to make a total of 15lb, then:
C + S = 15
We also want that the price per pound to be equal to 5$.
This means that the price of the 15 pounds will be the same as the price of the un-mixed candies.
C*$7.00 + $2.00*S = $5.00*15
Then we have a system of equations:
C + S = 15
C*$7.00 + $2.00*S = $5.00*15
To solve this system, we need to start by isolating one of the variables, i will isolate C in the first equation:
C = 15 - S
now we can replace that in the other equation:
(15 - S)*$7.00 + $2.00*S = $5.00*15
Now we can solve this for S.
$105 - $5.00*S = $75
$105 - $75 = $5.00*S
$30 = $5.00*S
$30/$5 = S = 6
Then there are 6 pounds of sugar candy, and we can use the equation:
C + S = 15
C + 6 = 15
C = 15 - 6 = 9
There are 9 pounds of chocolate candy in the mix.