Question 619934
on monday harold picked five donuts and six large coffees he paid $8.65 
on tuesday he picked three donuts and five coffees he paid $6.38. what's the cost of one donut and the cost of one large coffee
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Equation:
5d + 6c = 865 cents
3d + 5c = 638 cents
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Multiply thru 1st by 3:
Multiply thru 2nd by 5:
15d + 18c = 3*865
15d + 25c = 5*638
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Subtract and solve for "c":
7c = 595
c = 75 cents (cost on one large coffee)
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solve for "d":
3d + 5c = 638 cents
3d + 5*75 = 638
3d = 263
d = 87 2/3 cents (cost of one donut)
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Cheers,
Stan H.
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