Interest

INTEREST!

Interest is the money you pay back when you borrow money from the bank.

Its basically a formula of Principal x Rate x Time

Say that the Interest rate was at an annual rate of 8%

If you took out $100 for one year, it would be 1 (time) x 0.08 (rate) x $100 (Principal) which would equal $8 so you would have to pay $108 back to the bank for borrowing money instead of only $100

Now lets say you took out $500 for 8 years, that would make the formula...

8 (time) x 0.08 (rate) x $500 which would equal $320 that you would need to pay back

A way that you can remember the formula is by using letters...

P = Principal

R = Rate

T = Time

I = Interest

A way that I use to remember the letters is PRTI reminds me of party so I just think of an INTERESTing party:D works for me, thought it might help you during your next test.

Percent CHALLENGE!

Solve the following percent problem and post your answer as a comment. Be sure to explain all your steps!

Kora and Micah have lunch together. When the bill comes, Kora wants to leave 15% of the bill as a tip. Micah wants to leave 77¢ more, making the tip 20% of the bill. Calculate the amount of the original bill without the tip. Express your answer to the nearest cent.

Review of Percent

Hey everyone , I’m going to be talking about percentage, basically this is a review of things.

I am now going to show you three different ways of how to get a percent.

First way: 20% of 10 = __ * First of all, I will tell you, that “of” always means multiply (in math language). How to do that problem its fairly simple, all you have to do is put a decimal in front of the two. (You don’t need to put the 0) Then you put the multiplication sign and then put 10, because the question was 20% of 10 = __.

Second way: ___ % of 25 = 15 *This equation is different then the one I just showed you, but I do see something in this equation that sticks out to me which is “of” so that kind of makes it a little bit easier. What you have to do with that equation is cross multiply. You take x à (which means a known number), and put it out of hundred. Why you do that is because your trying to find the percent, and percent is always out of hundred that’s why you put the hundred bellow and why you put the x is because you don’t know what the number is. Then you just put fifteen over twenty five, because twenty five is what its multiplying out of and 15 is the answer. Next your cross multiply, so 15 times 100, and 20 times x. So 1500 = 20x then you divide 1500 and 20x, and you should get 60%.

Third way: 20% of __ =15 * This equation is not that different then the one I just showed you. The only thing that is different is that the x (un known number) is in a different place. Other wise everything is the same.

x = 75