one day the school

Question

one day the school store sells a total of 142 candy bars and bags of chips and makes a total of $194. If candy bars cost $1.50 each, and chips cost $1 each how many of each did they sel

Answer 1

What you are looking for:

number of candy bars + number of bags of chips= 142

($1.50 x 1 candy bar) + ($1 x 1 bag of chips)= $194

 

How to get there:

1. Rename the variables: candy bars will be represented by x and bags of chips will be represented by y.

2. Apply this to the formula:

x + y = 142

1.5x + 1y = 194

3. Multiply the second equation by -1

x + y = 142

(1.5x + 1y = 194)*-1

Result:

x + y = 142

-1.5x - 1y =-194

4. Add the equations together:

(x - 1.5x) + (y - 1y) = (142 -194)

Result:

-.5x = -54

5. Solve for x:

x = -54/-.5

Result:

x = 104

6. Now, plug x into each of the original functions

104 + y = 142
(1.5*104) + 1y = 194

 7. Then solve to get the y value:

y = 142 - 104

y = 194 - 156

Result:

y = 38

y = 38

8. Since both y values are the same, you only have to check your answers once.

104 + 38 = 142
(1.5 * 104) + (1 * 38) = 194

Result:

142 = 142

194 = 194

9. Since the check worked, your answer should be 104 candy bars and 38 bags of chips!