SOLUTION: Will you please help me with this problem? Write a system of two equations in two unknowns. Solve the system by using the addition method. « Mike paid $2.98 for three doughnuts

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Question 65196: Will you please help me with this problem?
Write a system of two equations in two unknowns. Solve the system by using the addition method. « Mike paid $2.98 for three doughnuts and two coffees. The next day, he paid $1.64 for two doughnuts and one coffee. How much does it cost for one doughnut and one coffee?
Thank you!
Answer by stanbon(48568) About Me  (Show Source):
You can put this solution on YOUR website!
Write a system of two equations in two unknowns. Solve the system by using the addition method. « Mike paid $2.98 for three doughnuts and two coffees. The next day, he paid $1.64 for two doughnuts and one coffee. How much does it cost for one doughnut and one coffee?
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1st: 3d+2c=2.98
2nd: 2d+ c=1.64
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Multiply 2nd by 2 to get:
3rd: 4d+2c=3.28
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Subtract 1st from 3rd to get:
d=0.30 ( Cost of one doughnut)
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Substitute into 2nd to solve for c, as follows:
2(0.30)+c=1.64
c=1.04 (cost of one coffee)
Cheers,
Stan H.