Percentages 1. Percentage

On TV or radio, we have heard that a bank has had a 7 percent of profits. That means that for every 100 coins, it has earned 7 times more and now it has 107 coins. The percentage of profit was 7%.

Another example: there was a VAT law that stipulated that all traders had to pay to the State a tax of six percent (6 %) of all sales. If a store has sold 100 Euros, it will pay 6 Euros to the state; if it had sold 200 Euros, it would have to pay 12 Euros.

You can read the lesson of how to solve problems.
Do these problems on a paper

 1. I am a seller and I have a profit of 7%. How much money will I earn if I sold 200 Euros? 2. What if I sold 400 Euros? 3. What if I sold 500 Euros?  2. Sales

During the year, we see sale posters in different ads. If it says 20%, this means that for every 100 coins that the product cost, the store will reduce 20 coins. If I buy a scarf that cost 100 coins and the store will reduce me 20, I have to pay 80 coins.
To find the percentage of an amount, we must multiply that percentage by the amount and then we must divide it by 100. For example: 20% of 2500 = (20 x 2500): 100 = 500. Here is another way to do it: 2500 x 0.20 = 500.

Solve these problems by assuming that the sale is 20%:

 1. A store offers all its items with 20%. How much money will the store reduce me for jeans that cost 25 Euros? 2. How much money will I pay for the previous jeans? 3. How much money will I pay for a shirt whose original price was 18 Euros? 4. What will be the discount of a tie that cost 10 Euros? 5. What will be the discount of a jersey that cost 24 Euros? 6. How much money will I pay for the previous jersey?

3. Simple Interest

When a family earns more money than it spends, they can save the extra money in a bank or saving bank or invest it in government bonds and receive a benefit. The benefit is called interest. If we deposit 100 Euros in a saving bank and the interest rate is 2%, after 1 year we will have 102 Euros. In two years we will have 104 Euros.

The formula for the simple interest is: Interest = capital x % x years.
If we deposit 400 Euros in a bank with 3% of interest rate for 8 years, we will get an interest of: n quantities.
400 x (3/300) x 8 = 400 x 0.03 x 8 = 96. How much money will I have? The sum of 400 + 96 = 496 Euros.

Solve these problems:

 1. Calculate the interest of 3400 Euros with an interest rate of 5 % for 3 years. 2. How much will we pay for 8000 Euros with an interest rate of 7.5% for 10 years? 3. Find the interest of 2550 Euros with an interest rate of at 4% for 4 years? 4. How much money will I have if I deposit 8500 Euros with an interest rate of 6% for 5 years? 5. A man has invested 10300 Euros in government bonds with an interest rate of 6.5 % for 4 years. After that time how much money will he have? 6. A friend had 4500 Euros and he deposited them in a bank with an interest rate of 3.5% for 4 years. How much is the sum among the capital and the interest?

4. Loans

A couple wants to get married and buy an apartment. They have savings but they need 12000 Euros, so they go to a bank to ask for a loan. They come to an agreement and the Bank grants them 12000 Euros with an interest rate of 5 % for 10 years. The couple will have to repay the capital and pay the interest.
For example: If we take a loan of 14000 Euros with an interest rate of 5 % for four years, the interest that we have to pay will be: 14000 x 0.05 x 4 = 2800 Euros. So we will have to pay those 2800 Euros plus 14000 (the amount that the bank lent). In total 16800 Euros.

Solve these problems:
 1. How much money will John return to a Bank for a loan of 14000 Euros with an interest rate of 5.5% for 7 years? 2. Peter asked for a loan to start a business with a capital of 6700 Euros with an interest rate of 4.5% for 3 years. How much money will he have to repay to the bank? 3. I asked for a loan of 2350 Euros with an interest rate of 6% for 5 years. What interest will I pay? 4. From the previous problem, how much money will I paid to the bank in total? 5. John asked for a loan of 12000 Euros with an interest rate of 6.75% for 15 years. How much money will he pay for the interest? 6. From the previous problem, how much money will he pay in total?

 | Educational applications | Mathematics | In Spanish  | To print

®Arturo Ramo García.-Record of intellectual property of Teruel (Spain) No 141, of 29-IX-1999
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