Question 1151842
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<pre>

According to the condition, the masses of zinc and copper in the alloy are 3x and 14x, where x is the common measure of masses.


The value of x is unknown now, but we can easily find it from the other condition of the problem


    14x = 560,


which gives  x = 560/14 = 40.


Thus the mass of zinc in the alloy is 3*40 = 120 lb.    <U>ANSWER</U>
</pre>


Another way to setup the governing equation is THIS :



<pre>
Write the proportion


    {{{Z/560}}} = {{{3/14}}},


based on the condition.


From the proportion, the mass of zinc in the alloy is


    Z = {{{(560*3)/14}}} = 40*3 = 120 lb.      the same <U>ANSWER</U>
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Solved.