Cost of the spa treatment = $42
Percentage of sales tax = 6%
Percentage of tips = 20%
Normally the tips amount is calculated before adding sales tax.
Then
Amount of tips given = (20/100) * 42
= (1/5) * 42
= 8.40 dollars
Amount of sales tax taken = (6/100) * 42
= 252/100
= 2.52 dollars
Then
The total amount spent for spa treatment = (42 + 8.40 + 2.52) dollars
= 52.92 dollars
So we can see that $52.92 has been spent in total for spa treatment and this amount includes a sales tax of $2.52 and a tip of $8.40.
