Answer:
$18.00
Step-by-step explanation:
Start by working out 10%, that's easy:
15 ÷ 10 = 1.5
That means a 10% tip would be $1.50, so a 20% tip would be twice that amount:
1.50 x 2 = 3
A 20% tip is $3.00, and added on to the original $15.00, the total is $18.00
