<PRE><B>Question 534270</B>
&lt;B&gt;Check my profile and contact me for one on one online tutoring.&lt;/B&gt;&lt;P&gt;

We don&#39;t know how much $60 coffee should be used.  Call it x.&lt;P&gt;

We do know how much of the $90 coffee is used.  70 lbs.&lt;P&gt;

When mixed, there is x + 70 pounds of coffee, and that is worth $70/lb.&lt;P&gt;

We can set up an equation:  60x + 6300 = (x+70)*70.&lt;P&gt;

Solving for x reveals the answer.  &lt;P&gt;

60x +6300 = 70x +4900 --&gt;  1400 = 10x  ---&gt; 140=x</PRE>