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## Class 7 math (India)

### Course: Class 7 math (India) > Unit 8

Lesson 6: Simple interest# Intro to simple interest

What is the meaning of paying interest when we borrow money? What is the meaning of the word "principal" here? Created by Aanand Srinivas.

## Want to join the conversation?

- how u will know what formular to do(1 vote)
- Simple Interest Equation (Principal + Interest)

A = P(1 + rt)

Where:

A = Total Accrued Amount (principal + interest)

P = Principal Amount

I = Interest Amount

r = Rate of Interest per year in decimal; r = R/100

R = Rate of Interest per year as a percent; R = r * 100

t = Time Period involved in months or years

From the base formula, A = P(1 + rt) derived from A = P + I and I = Prt so A = P + I = P + Prt = P(1 + rt)

Note that rate r and time t should be in the same time units such as months or years. Time conversions that are based on day count of 365 days/year have 30.4167 days/month and 91.2501 days/quarter. 360 days/year have 30 days/month and 90 days/quarter.

Simple Interest Formulas and Calculations:

Use this simple interest calculator to find A, the Final Investment Value, using the simple interest formula: A = P(1 + rt) where P is the Principal amount of money to be invested at an Interest Rate R% per period for t Number of Time Periods. Where r is in decimal form; r=R/100; r and t are in the same units of time.

The accrued amount of an investment is the original principal P plus the accumulated simple interest, I = Prt, therefore we have:

A = P + I = P + (Prt), and finally A = P(1 + rt)

Calculate Total Amount Accrued (Principal + Interest), solve for A

A = P(1 + rt)

Calculate Principal Amount, solve for P

P = A / (1 + rt)

Calculate rate of interest in decimal, solve for r

r = (1/t)(A/P - 1)

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = (1/r)(A/P - 1)(32 votes)

- What currency is used in this video?(5 votes)
- The currency used in the video is the Indian currency which is expressed in Rupees.(12 votes)

- I know nobody asked but here are the definitions and formulas for anyone who needs them;

SIMPLE INTEREST: (SI)

Amount of money paid or earned for the use of the other money paid.

FORMULA: SI= P*R*T/100

PRINCIPAL: (P)

The amount of money borrowed/invested

FORMULA: P= SI*100/R*T

RATE: (R)

the annual interest rate written as a decimal.

FORMULA: R= SI*100/P*T

TIME: (T)

the amount of time in years

(if time is given in months, it must be written as a fraction. For example, 6 months would be written as 6/12 year or 0.5 years)

FORMULA: T= SI*100/P*R

AMOUNT (A) FORMULA: A= P+SI(10 votes) - Hi! I was studying simple interest for my 7th grade math class, and for some of the lessons provided on the topic Simple Interest, I've been struggling. I have a question and an example problem I wanted to solve. If you are only given specific parts of simple interest such as the time and principal but no rate, how could we find the missing values? Are there specific formulas? And what if the time was 1? How would I solve with 1 year? Also, I wanted to know how to solve this example problem I've found on Google:

If interest paid by Micheal is one-fifth of the total amount he has to pay after a certain time period, what is the time period if rate of interest was 25%?

Does anyone know how to solve this? Thanks!(6 votes) - I = Interest Amount

r = Rate of Interest per year in decimal; r = R/100

R = Rate of Interest per year as a percent; R = r * 100

t = Time Period involved in months or years

From the base formula, A = P(1 + rt) derived from A = P + I and I = Prt so A = P + I = P + Prt = P(1 + rt)

Note that rate r and time t should be in the same time units such as months or years. Time conversions that are based on day count of 365 days/year have 30.4167 days/month and 91.2501 days/quarter. 360 days/year have 30 days/month and 90 days/quarter.

Simple Interest Formulas and Calculations:

Use this simple interest calculator to find A, the Final Investment Value, using the simple interest formula: A = P(1 + rt) where P is the Principal amount of money to be invested at an Interest Rate R% per period for t Number of Time Periods. Where r is in decimal form; r=R/100; r and t are in the same units of time.

The accrued amount of an investment is the original principal P plus the accumulated simple interest, I = Prt, therefore we have:

A = P + I = P + (Prt), and finally A = P(1 + rt)

Calculate Total Amount Accrued (Principal + Interest), solve for A

A = P(1 + rt)

Calculate Principal Amount, solve for P

P = A / (1 + rt)

Calculate rate of interest in decimal, solve for r

r = (1/t)(A/P - 1)

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = (1/r)(A/P - 1)

I hope it will help you all If yes then hit a 🔺👈🏻👈🏻 like...(5 votes) - interest and profit is a very different thing?(4 votes)
- Principal = 9300=9300equals, 9300 rupees

Annual rate of interest = 13 \%=13%equals, 13, percent

Total amount = 17{,}763=17,763equals, 17, comma, 763 rupees

Period ==equals

years(4 votes) - i'm confused and when will we se this irl(3 votes)
- We see this irl with economics(3 votes)

- Is there another video on this exact topic in American currency.(1 vote)
- You can also go on Youtube and find a video on this in American Currency if you want to.(4 votes)

- What is the difference between simple interest and compound interest?(3 votes)