<span>It's easy enough. Solving looks like that: p(roll of 8)+p(roll of 12) =</span>

Hope everything is clear.
$3.50 being the amount the item <em>t</em> costs and <em>t</em> being the number of this item.
Answer:
I believe that the answer is 6 inches
-2x -4<10
+4 +4
-2x <14
x>-7