<PRE><B>Question 756919</B>
Equation 1:  x/y = 3/5&lt;P&gt;
5x = 3y&lt;P&gt;
x = 3y/5&lt;P&gt;
Equation 2:(x+10)/(y+10) = 5/7&lt;P&gt;
7(x+10) =5(y+10)&lt;P&gt;
7x + 70 = 5y + 50&lt;P&gt;
Substitute in the value of x from equation 1.&lt;P&gt;
7(3y/5) + 70 = 5y + 50&lt;P&gt;
21y/5 + 70 = 5y + 50&lt;P&gt;
20 = 5y - 21y/5&lt;P&gt;
20 = 25y/5 - 21y/5 = 4y/5&lt;P&gt;
100 = 4y&lt;P&gt;
25 = y&lt;P&gt;
Substitute that back into equation 1:  x = 3*25/5 = 75/5 = 15</PRE>