Question 114271
Big Burger is giving away gold and silver coupons. the gold coupons are worth 15 points and the silver coupons are worth 10 points. Maddy is saving coupons so she can get free Super Big Burgers. 
So far Maddy has 16 copupons worth 215 points. How many gold coupons and how many silver coupons does Maddy have? 
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Let # of gold coupons be "g"; Let # of silver coupons be "s"
EQUATIONS:
g + s = 16
15g + 10s = 215
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Solve by substitution:
s = 16-g
15g + 10(16-g) = 215
15g + 160-10g = 215
5g = 55
g = 11 (# of gold coupons)
s = 16-11 = 5 (# of silver coupons)
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Cheers,
Stan H.