Answer: 10lbs of the $1.5 a pound chocolate was used in the mixture.
20lbs of the 90¢ a pound chocolate was used in the mixture.
Step-by-step explanation:
Let x represent the number of pounds of the $1.5 a pound chocolate that was used in the mixture.
Let x represent the number of pounds of the 90¢ a pound chocolate that was used in the mixture.
The total number of pounds in the mixture is 30. It means that
x + y = 30
A mixture of 30 lbs. of candy sells for $1.10 a pound. This means that the total cost of 30lbs of the mixture is
30 × 1.1 = $33
This means that
1.5x + 0.9y = 33- - - - - - - - -- - 1
Substituting x = 30 - y into equation 1, it becomes
1.5(30 - y) + 0.9y = 33
45 - 1.5y + 0.9y = 33
- 1.5y + 0.9y = 33 - 45
- 0.6y = - 12
y = - 12/ - 0.6
y = 20
x = 30 - y = 30 - 20
x = 10