How do I add a percentage (%) tip to a total of a bill? (Ex - Total : 3.00 with a %18 tip)

To calculate a gratuity or tip on any calculator it is a simple multiplication. In general, the tip amount is the cost times 0.xx and your total including tip, is the cost times 1.xx where xx = the percent you want to leave.  If you want to leave a 20% tip, multiply the cost by 0.20 to get the tip amount or multiply the cost by 1.20 to get the total including tip. If you want to leave a 18% tip, multiply the cost by 0.18 to get the tip amount or multiply the cost by 1.18 to get the total including tip.

Let's say you and a friend had dinner that cost $26.50.  You had good service and want to leave an 18% gratuity.  Put the percentage in decimal form (0.18) then multiply the cost by this number.

26.50 * 0.18 = 4.77.  So your tip is $4.77.

An easy way to get the total amount, dinner plus tip, is to multiply the total by 1.18. 26.50 * 1.18 = 31.27.  This works mathematically because you want to know your original cost plus the tip which is written as 26.50 + (26.50 * 0.18) = ?  Factoring out the 26.50 from this equation you get 26.50 * (1 + 0.18) = 26.50 * 1.18.

How to calculate a tip in your head

You can get a good approximation of a tip by doing it in your head this way.

You can find 10% of your bill by moving the decimal one place to the left.  If 26.50 is 100% then 10% is 2.65.  Since 20% is 2 times 10%, 20% of the bill is 2.65 + 2.65 = 5.30.  Now you know the tip you could leave ranging from poor to good, $2.65 to $5.30.  To find 15%, halfway in between, we know 15% is 10% plus 1/2 of 10% (5%).  2.65 plus about 1.30 is 3.95.

Now you have

10% is 2.65 - by moving decimal 1 place left

15% is 3.95 - 10% + 1/2 of 10%

20% is 5.30 - 10% * 2

This is plenty of information to make a good guess at the tip amount you should leave.  If you decide on about 18%, 4.50 to 5.00 would be a safe guess.

Hope this helps!!! Please mark Brainliest because no matter what you are the Brainliest of all!

put to percentage as a decimal (ex. 0.18) then you add that to the total amount

it is x=-4

step-by-step explanation:

21

jk it's 20

step-by-step explanation: