SOLUTION: Alexandra purchases two doughnuts and three cookies at a doughnut shop and is charged $3.30. Briana purchases five doughnuts and two cookies at the same shop for $4.95. All the dou

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Question 181866: Alexandra purchases two doughnuts and three cookies at a doughnut shop and is charged $3.30. Briana purchases five doughnuts and two cookies at the same shop for $4.95. All the doughnuts have the same price and all the cookies have the same price. Find the cost of one doughnut and find the cost of one cookie.
Please show work.
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Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website!

Let the cost of one donut be d and the cost of one cookie be c.

Then A's purchase is described by:

And B's purchase is described by:

Note the change from expressing the cost in dollars to expressing the cost in cents -- that gets rid of the decimal fractions and makes things neater.

Solve the system of two equations for the values of d and c remembering that the answers will come out in cents which you can convert back to decimal parts of a dollar if you wish.

Hint: Solve by the elimination method. Multiply the first equation by 2 and the second by -3 to eliminate the c variable.

John