I sell cookies for $3 and muffins for $7. Yesterday, I made $129. I sold a total of 27 items. How many of each did I sell? CAN SOMEONE ANSWER IT PLZ

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Step-by-step explanation:

Often, you can work these problems in your head.

If you sold all cookies, your revenue would have been 27×3 = 81. It was 129-81 = 48 more than that. Each muffin generates 4 more revenue than a cookie dies, so there must have been 48/4 = 12 muffins. The 27-12 = 15 were cookies.

You sold 15 cookies and 12 muffins.

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If you let a variable represent the most expensive item (m for muffins), then you can write an equation for the revenue. You may recognize that some of the steps in the solution match the "verbal" solution above.

  3(27 -m) +7m = 129

  4m +81 = 129

  4m = 129 -81 = 48

  m = 48/4 = 12 . . . muffins

  27-12 = 15 . . . cookies

it would be 6xy and -16xy.