7% tax on a $115 coat:
You can't use 7% in a calculation, so change it to a number that you can.
Divide the percent (%7) by %100. /

Multiply 0.07 by what you paid for the coat, $115.
0.07 × $115.00 = $8.05
Now that you know the amount of the tip you are going to give, add it to the total of the coat.
$115 + $8.05 = $123.05
Answer:
$123.05