<PRE><B>Question 1022863</B>
OK, I&#39;ll take you up to the equations. If you get stuck email me.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20,000 at 0.07 and 0.09 earn 1,550.
Let&#39;s call the amount invested at 0.07 x. 
The rest of the money is invested at 0.09... how much is this amount? Well, out of 20,000, if x is invested at 0.07, that leaves 20,000-x to invest at 0.09:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0.07x+0.09(20,000-x) = 1,550
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You take it from there.
J</PRE>