David received a 20% tip on a bill of $86.40. how much was his tip?

To find the tip of the bill. You will need to find how much of $86.40 is 20%. In this question, they're asking how much is the tip, not how much will the final price be.

When you multiply a percentage you move the decimal point 2 times to the left: 20. → .20

You would multiply $86.40 by .20

When you solve it 86.40 × .20 = 17.28

$17.28 is 20% of $86.40

$17.28 will be the amount he got for his tip.

My mom keeps saying i need to know how to do this in my head. I'll do it with a calculator just to be safe lol.

So to do this all we have to do is multiply 86.40 x .20 and we get  $17.28

$17.28<--- Answer.

-Seth

step-by-step explanation:

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