Download presentation

Presentation is loading. Please wait.

Published byImmanuel Sobey Modified over 2 years ago

1
Simple Interest Math 8

2
Simple Interest Can be interest gained (earned) or interest paid Interest paid- costs you money * loans * credit cards Interest earned- you receive money –Savings accounts –Investments

3
Interest Formula I = prt (Interest = principle x rate x time) I = interest amount ($) p= principle – original amount ($) r = rate- interest percent (%) –Turn into a decimal to calculate t = time- in years –If not given in years, divide the number of months by 12, you may get a decimal

4
So… Basically, you are just substituting in numbers and solving for the missing variable. Make sure to… –Change % to decimal –Change months to years (if necessary) –Check what the question is asking for ( I, p, r, or t)

5
Example Emily buys a car for $19,500. The interest is 5% and the loan is for 5 years. What is the interest Emily will pay on the car AND what is the total amount she will have paid at the end of the five years?

6
Example #1 Emily buys a car for $19,500. The interest is 5% and the loan is for 5 years. What is the interest Emily will pay on the car AND what is the total amount she will have paid at the end of the five years? I = prt I =x p= 19,500 r=.05 (5% converted to decimal) t= 5

7
Calculate I = prt I =x p= 19,500 r=.05 (5% converted to decimal) t= 5 x = (19,500) (.05) (5) x =

8
Calculate I = prt I =x p= 19,500 r=.05 (5% converted to decimal) t= 5 x = (19,500) (.05) (5) x = 4,875 The interest she will pay is $4875. Add that to the principle for the total amount she will have paid at the end of 5 years. $19,500 + $4,875 = $24,375

9
Example #2 Darren wants to buy a house for $245,00. The current interest rate is 4.5% and the mortgage is for 30 years. Find the interest Darren will pay at the end of 30 years.

10
Example #2 continued Darren wants to buy a house for $245,00. The current interest rate is 4.5% and the mortgage is for 30 years. Find the interest Darren will pay at the end of 30 years. What is the formula you will use? _________________________ I = p = r = t =

11
Example #2 Darren wants to buy a house for $245,00. The current interest rate is 4.5% and the mortgage is for 30 years. Find the interest Darren will pay at the end of 30 years. I = prt (Interest = principle x rate x time) I = x p = 245,000 r =.045 t = 30

12
Example #2 Darren wants to buy a house for $245,00. The current interest rate is 4.5% and the mortgage is for 30 years. Find the interest Darren will pay at the end of 30 years. I = prt (Interest = principle x rate x time) I = x p = 245,000 r =.045 t = 30 x = (245,000)(.045)(30) x = $330,750

13
Example #3 Rachel needs to buy new furniture for her apartment. The furniture costs $3500. She is taking out a loan to pay for the furniture and she will pay $1207.50 in interest during the 3 year loan period. What is the interest rate on her loan?

14
Example 3 Rachel needs to buy new furniture for her apartment. The furniture costs $3500. She is taking out a loan to pay for the furniture and she will pay $1207.50 in interest during the 3 year loan period. What is the interest rate on her loan? I = prt I = 1207.50 p= 3500 r= x t= 3 1207.50 = (3500)(x)(3) 1207.50= 10,500x.115= x *** Change back into a % for the rate Her interest rate is 11.5%.

15
A helpful hint If it helps you to remember what you are trying to solve, use the first letter of the “missing” chunk of info as the variable. So, if I want to find out the rate of interest like we did in the last example, I would set up my equation like this: I = prt 1207.50 = (3500)(r)(3) Then solve for r

Similar presentations

OK

9-10 6 th grade math Using the Interest Formula. Objective To use the simple interest formula to calculate interest and find the total amount earned or.

9-10 6 th grade math Using the Interest Formula. Objective To use the simple interest formula to calculate interest and find the total amount earned or.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Convert word doc to ppt online viewer Ppt on summary writing for kids Ppt on structure of atom class 11th Ppt on mapping space around us Psychology ppt on motivation Ppt on social etiquettes tips Ppt on condition monitoring software Inspirational ppt on positive attitude free download Ppt on the road not taken theme Ppt on historical places in delhi