posted by Samantha .
A book has been discounted 20% and now sells for $15. How much did it cost before the discount?
After we took off 20%, doesn't the $15 represent 80% of what it used to cost?
x = 15/.8
test the answer by taking 20% of that, and subtracting it.
Do we get $15 ?
That is one of the choices so my guess is that that is correct. Thank you! =]