Question 1052124
<pre><b>
x = number of 50 centavo coins
y = number of 10 centavo coins

Thirty coins....

    x + y = 30

consisting of 50 centavo coins and 10 centavo coins are worth 700 peso.

50x + 10y = 700

Solve by substitution.  If you can't do that, I'll help you if
you tell me in the thank-you note box below.

Edwin</pre></b>