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22 votes
22 votes
3. Juan goes to the book fair where paperback books are $6 and hardbackbooks are $8.50. Juan buys four paperback and 3 hardback books. He payswith a $50 bill.1 point3a. Edward wrote the expression below to represent how much changeJuan should get back. However, there is something wrong with his work.Explain the mistake and help Edward fix the expression. *50 - 6 x 4 + 8.5 x 3Your answer3b. How much change does Juan get back?*1 point

User Vivek Athalye
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1 Answer

10 votes
10 votes

Let a paperback book be reprsented by x

Let a hardback books be reprsented by y

A paperback book costs $6 and a hardback book costs $8.50.

If Juan buys 4 paperback books and 3 hardback books, the statement can be expressed below as,


4x+3y

If he pays $50, it can be represented as


\begin{gathered} 50-(4x+3y) \\ 50-4x-3y \\ \text{Where} \\ x=6,y=8.5 \\ 50-(6*4)-(8.5*3) \\ 50-6*4-8.5*3 \end{gathered}

Edwards mistake was adding a positive sign to (8.5 x 3) after opening the bracket instead of a negative sign and to avoid such mistake, he should have added parenthesis in other to sum up the cost of what he bought.

To find Juna's change below,


50-(6*4)-(8.5*3)=50-24-25.5=50-49.5=\text{\$0.50}

Juan's change is $0.50

User Chrskly
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