Mr. Woods had $24 to spend on seven pencils. After buying them he had $10. How much did each pencil cost?
I would say each pencil costs $2.
We would set up an equation:
$24 = 7x + $10 where x is the price per pencil.
Now, we would substitute values in for x:
$24 = 7(1) + $10
$24 = 7 + $10
$24 = $17 <- Not True
$24 = 7(2) + $10
$24 = 14 + $10
$24 = $24 <- True!
So, each pencil costs $2.
Hope this helps. :)