If you want to leave a 15% tip on a bill of $18.06, you should pay $20.77.
To calculate the tip amount, you can multiply the bill total by 0.15 (15% as a decimal):
Tip amount = $18.06 x 0.15 = $2.71
Then, to find the total amount you should pay, you can add the tip amount to the bill total:
Total amount = $18.06 + $2.71 = $20.77
Therefore, you should pay $20.77 if you want to leave a 15% tip on a bill of $18.06.