Let r represent cost of each box.
We have been given that Mia bought 10 boxes of brownies. So cost of 10 boxes would be [tex]10r[/tex].
We have been given that Mia bought 10 boxes of brownies at the store for a total of $64. The tax on the purchase was $5. So the total cost of 10 boxes would be cost of 10 boxes plus tax.
We can represent this information in an equation as:
[tex]10r=64+5[/tex]
We can subtract 64 from both sides as:
[tex]10r-64=64-64+5[/tex]
[tex]10r-64=5[/tex]
Therefore, our required equation is [tex]10r-64=5[/tex] and option 'c' is the correct choice.
