Question 1156877
.
<pre>

Let x = original mass of silver in the alloy (in grams); y = mass of of copper.

After adding 25% of the original mass of silver, there are x+0.25x = 1.25x grams silver in the alloy.


From the condition, you have these two equations


    x - y = 50   grams         (1)   (the difference of the original amounts)

    {{{(1.25x)/(1.25x + y)}}} = 0.6             (2)   (silver concentration of 60% after adding)


Simplify equation (2)

    1.25x = 0.6*(1.25x + y)

    1.25x = 0.75x + 0.6y.

    0.5x = 0.6y                (3)


From equation (1), express x = 50 + y and substitute it into equation (3).

    0.5*(50 + y) = 0.6y

    25 + 0.5y    = 0.6y 

    25           = 0.6y - 0.5y = 0.1y

    y = 25/0.1 = 250.


Then from equation (1),  x = 250 + 50 = 300.


<U>ANSWER</U>.  Originally, the alloy was 300 gram solver and 250 grams copper.
</pre>

Solved.


You may check that my solution is correct.