Question 133662
if 20lb of rice and 10lb of potatoes cost $16.20, and 30lb of rice and 12lb of potatoes cost $23.04, how much will 10lb of rice and 50lb of potatoes cost?
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Let "r" be cost of rice; Let "p" be cost of potatoes.
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EQUATIONS:
20r + 10p = 16.20
30r + 12p = 23.04
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Multiply 1st equation by 3; Multiply 2nd equation by 2
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60r + 30p = 3*16.2
60r + 24p = 2*23.04
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Subtract 2nd from 1st to get:
6p = 3*16.2 -2*23.04
6p = 2.52
p = 0.42 (price of a pound of potatoes is 42 cents)
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Substitute to solve for "r".
20r + 10*0.42 = 16.2
20r + 4.2 = 16.2
20r = 12
r = 0.6 (price of a pound of rice is 6 cents)
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Cheers,
Stan H.