Question

Eric takes classes at both Westside community college and Pinewood community college. At westside per credit hour and at pinewood class fees are $115 per credit hour. Eric is taking a combined total of 17 credit hours at the two schools. suppose that he is taking W credit hours at Westside. Write an expression for the combined total dollar amount he paid for his class fees.

Answer 1

Represent credit hours at each of the two schools with two different variables

`\begin{gathered} x=\text{credit hours at Westside Community College} \\ y=\text{credit hours at Pinewood Community College} \end{gathered}`

From the question, write out the equation that relates the credit hours of the two schools

`x+y=17====\text{equation}(1)`

From the question, it can be observed that the credit hours at Westside is represented as W.

Therefore, the equation becomes

`W+y=17=====\text{equation (2)}`

Represent the dollar amount per credit hour at westside Community College using a and the total dollar amount for the two classes to be b. Then b becomes

`b=aW+115y`

If a is given as$98, then b becomes

`b=98W+115y======\text{equation (3)}`

Make y the subject of the equation (2) and substitute in equation 3

`\begin{gathered} W+y=17 \\ y=17-W \end{gathered}`
`\begin{gathered} b=98W+115y \\ b=98W+115(17-W) \\ b=98W+1955-115W \\ b=1955-17W \end{gathered}`

Hence, the expression for the combined total dollar amount he paid for his class fees is 1955 - 17W