First, 5% sales tax is 5/100 or 0.05.

So you say 5%of$1500.00. "Of" always means multiply so:

0.05 x $1500.00 = $75.00

Then, the total cost is the $1500.00 + the sales tax:

1500 + 75 = $1575.00

An easy way to do this in your head is to use 10%:

10% of $1500 is 0.1 x 1500 = $150.00

5% is half of 10%, so half of $150 is $75. So the 5% sales tax adds $75 to the price (1500+75=$1575).