Delilah and a group of friends had excellent service at a restaurant. They would like to give the server a 25 percent gratuity on their $140 bill.

Here we want to calculate the 25% of $140.

Well, first we assume that:

$140 = 100%.

Now, assuming that, we can write the equation:

X = 25%

Where X is the 25% of $140.

Then we have the equations:

$140 = 100%

X = 25%

Let's take the quotient between these equations:

$140/X = (100%/25%)

Now let's solve this for X:

X = (25%/100%)*$140 = 0.25*$140 = $35

Then the tip will be of $35

answer: 48

just remember to use pemdas:

parentheses

expressions

multiplication

division

addition

subtraction