Answer:
Step-by-step explanation:
First we need to find 20% of their bill-$40.
So we write a proportion with fractions.
20/100 = x/40
Then we cross multiply. So 40 and 20 will get multiplied, and 100 and x will get multiplied. We will get this:
800 = 100x
Divide both sides by 100 to solve this.
Then we will get:
$8 = x or x = $8
Now that we know 20% of the bill this will also represent the tip. Our tip is $8.