you want to leave a tip for a meaol that cost $17.95.

Question

if all you have is $3.00, what percentage tip will you be able to leave? use a percent equation and a proportion

Answer 1

Hi Amy,

 

Do you mean if all you have is $3 to give as a tip, what percent is that out of $17.95 that you paid for your meal?

 

To find out all you have to do is divide 3/17.95

 

Why is that and how do you solve the proportion? Well first you have to understand what percent means. Percent means "out of 100," and you will see why this is important soon.

 

If you could divide 17.95 into 100 peices, how big would each peice be?

 

17.95 divided by 100 is .1795, so 17.95 represents your 100 total pieces.

 

Next you have to figure out how many pieces of the .1795 go into $3, and this will tell you how may .1795 pieces are in 3, or how many .1795 out of the total 100 (17.95) are in $3, that is why you are trying to figure out what percent 3 is out of 17.95

 

You represent this as a proportion in the following way:(3 / 17.95) = (x / 100)

 

 

To solve for x, multiply both sides of the equation by 100: (100* 3) / 17.95 =  (x * 100) / 100

 

(The 100 cancels out on the right hand side)

 

and you have 300/17.95 = x. The answer will be a decimal number between 1 and 100 that will be you percent. It will be the same as what 3 out of 17.95 is.

Answer 2

Hi Amy--

 

so, your 3.00 is "_______ percent of 17.95," so...

 

3.00 is to 17.95 as _____ is to 100

 

(I'm going to do the money amounts as cents for now, so you don't have to worry about decimal points...)

 

300/1795 = n/100

 

cross multiply 300 x 100 = 30,000, and 1795 x n = 1795n

 

1795n = 30,000, so n = 16.71

 

so if your bill was 17.95 and you left a $3.00 tip, you left a 16.71 percent tip.

 

(Your waiter was hoping for a bit more, but it's not too bad!) 

 

Hope this helps!

 

Matt