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mathematics

class VII

#### Key Concepts

simple interest, principal, interest, amount, rate, profit and loss

#### essential questions

1. What is simple interest? How do we use it in everyday life?
2. What do various variables represent?
3. How can I use percent's to calculate simple interest?
4.What is profit and loss and how do we use it in real life?

#### Remembering:

Simple Interest:

1. Principal= Rs 100000 Rate of interest =8% Time = 8 years. Calculate the simple interest?

#### understanding:

Simple Interest

1. Ryan deposited Rs 200000 in a savings account at the interest rate of 4 %. How much simple interest will he earn in 5 years?
2. If Rs 54000 has been invested in an account at a savings rate of interest at 5% per annum. How much time will it take to increase the original amount by Rs 7500?
3. Anna invested \$2500 at an annual rate of 5%. How long will it take until Anna earns \$ 1125?

Profit and Loss

1. James buys a video game for his Xbox for \$49.99, a controller for \$34.95, and a walk through manual for \$19.99. The sales tax in his area is 8.25%. What will be the total cost of his purchase?
2. If the market price of an article Rs 400 and it is sold at a discount of 10%, find the net selling price.
3. If the list price of a bicycle is Rs 1000 and it is sold for Rs 900, find the discount percent.
4. If the article is sold Rs 450 after allowing a discount of 10% find the list price of the article.

#### Application:

Simple Interest

1. Garima borrowed Rs 40000 from bank as a personal loan at interest rate of 8% per annum. She repaid the amount in 2 years. How much more did she pay from the borrowed money? What the percentage was this extra amount of the original money borrowed.
2. Kelly puts \$350 in a savings account. The savings account accrues interest at a flat rate of 1.05% a month. How much will the account be worth in 7 months?

Profit and Loss:

1. Ela buys skateboards for her store. She mark-ups up the prices by 40% of what she paid for them. If she purchases a gold series skateboard for Rs7550, how much will she charge for the skateboard in her store?
2. Tina has gone for a sale. Everything on the shelf is 35% off the marked price. She falls in love with a pair of red heels that are marked Rs 649. What will the actual selling price be?

#### Analysis:

Profit and Loss:

1. A trader marked his goods at 20% above the cost price. If the customer allows a discount 10%, find his profit percent.
2. A bicycle dealer allows 10% discount and still makes a profit of 20% on his bicycle. If total profit he makes is Rs150, find the list price of the bicycle.
3. A trader marked his goods at 20% above the cost price. If he gives 10% discount to his customers. Find his profit percent.