To calculate how much money you will have left after purchasing the book, we need to consider the cost of the book and the sales tax.
The cost of the book is $14.00. Adding 15% sales tax to the cost gives us:
$14.00 + 15% of $14.00 = $14.00 + ($14.00 * 0.15) = $14.00 + $2.10 = $16.10.
Therefore, after purchasing the book, you will have $20.00 - $16.10 = $3.90 left.