<PRE><B>Question 616907</B>
 in a metal alloy, the ratio of zinc to copper is 3 to 15. If there are 630 pounds of copper, how much zinc is there?
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3:15 is the same as 3x:15x where 3x is zinc and 15x is copper.
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Equation:
3x + 15x = 630
18x = 630 
x = 35
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Amt of zinc = 3x = 3*35 = 105 pounds
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Cheers,
Stan H.
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