Kyle filled 6 10-oz cup(s), 11 14-oz cup(s), and 4 20-oz cup(s).
Let's define the variables:
x = number of 10-oz cups of coffee sold.
y = number of 14-oz cups of coffee sold.
z = number of 20-oz cups of coffee sold.
We know that:
Kyle served 21 cups of coffee, then:
x + y + z = 21
He used 294 ounces of coffee, then:
x*10 oz + y*14 oz + z*20 oz = 294 oz
He collected a total of $24.35, then:
x*($0.95) + y*($1.15) + z*($1.50) = $24.35
Then we have a system of 3 equations:
x + y + z = 21
x*10 oz + y*14 oz + z*20 oz = 294 oz
x*($0.95) + y*($1.15) + z*($1.50) = $24.35
To solve this, the first thing we need to do is isolate one of the variables in one of the equations, let's isolate x in the first one.
x = 21 - y - z
Now we can replace this in the other two equations to get:
(21 - y - z)*10 oz + y*14 oz + z*20 oz = 294 oz
(21 - y - z)*($0.95) + y*($1.15) + z*($1.50) = $24.35
Now we can simplify these two equations:
y*4 oz + z*10 oz = 294 oz - 210oz = 84 oz
y*($0.20) + z*($0.55) = $24.35 - $19.94 = $4.40
Now we need to do the same thing, we need to isolate one of the variables in one of the equations, we can isolate z in the first one:
z*10 oz = 84oz - y*4 oz
z = (84oz - y*4 oz)/10oz
z = 8.4 - y*0.4
Now we can replace this in the other equation:
y*($0.20) + ( 8.4 - y*0.4)*($0.55) = $4.40
Now we can solve this for y.
y*($0.20) + $4.62 - y*$0.22 = $4.40
y*$0.02 = $4.40 - $4.62 = $0.22
y = $0.22/$0.02 = 11
Now that we know the value of y, we can use:
z = 8.4 - y*0.4
z = 8.4 - 11*0.4 = 4
Now that we know the value of z and y we can use:
x = 21 - y - z
x = 21 - 11 - 4 = 6
Then we found:
x = 6
y = 11
z = 4
this means that:
Kyle filled 6 10-oz cup(s), 11 14-oz cup(s), and 4 20-oz cup(s).
If you want to learn more about systems of equations, you can read:
https://brainly.com/question/20067450
