Estimate a 15% tip for each amount.

$9.89

$27.59

2 answers

0.15 * 10 = $1.50

10% of 28 = 2.80
2.80 * 2 = 5.60

The tip should be about half way between 2.80 and 5.60
Thank you and I'm sorry for accidentally posting a few times. I'm truly sorry for asking the same question repeatedly because it said it wasn't submitting because there was no signal.