20% Tip = $2.58 Total Amount: $15.43
Explanation:
An easy way to solve a problem, where the percentage ends in a 0, is to find 10% of the original number. 12.86 is our starting number, so finding 10% of that is simply moving the decimal place 1 to the left, making 10% = 1.29.
To find 20% Just Multiply 1.28 (10%) by 2, which is 2.58. Add this amount to 12.86 and you get $15.43.
Another way to solve the problem is simply to multiply $12.86 * 1.20, which would give you $15.43 as well.