Question 793682
Ben has 20 coins. They are all quarters, dimes, or nickels. 
What is the greatest amount of money Ben could have if seven are nickels?
<pre>
Let the other 13 coins all be quarters.  
7 nickels and 13 quarters amounts to $3.60
</pre>
What is the smallest amount if three are quarters?
<pre>
Let the other 17 coins all be nickels.  
3 quarters and 17 nickels amounts to $1.60

Edwin</pre>