# Percentages - examples - page 12

1. Energy saving
They were released three different, independent inventions saving 12%, 15% and 25% energy. Some considered that while the use of these inventions, the total savings will be 12% + 15% + 25% = 52%. Is this true? How much percent of energy will save all thre
2. Square - increased perimeter
How many times is increased perimeter of the square, where its sides increases by 150%? If the perimeter of square will increase twice, how much% increases the content area of the square?
3. Copy typist
Typist for 12 hours rewritten 15% of the manuscript. After how many hours he will done 35% of the manuscript?
4. Washing machine
The price of washing machine was decreased by 21% and then by 55 € due small sales. After two price decreases cost € 343. How much was originally cost?
5. Salary in enterprise
The average salary in the company is 27 000 CZK, 30% of workers have the lowest average income of 19 thousand CZK. There were an increase in the salary in this group by 2%. How much % increased the average salary across the company?
6. The rod
The rod is painted in four colors. 55% of the bar is painted in blue, green 0.2 of rod, 1/8 is brown and the remaining 45 cm of white. How long is rod?
7. Compound interest
Compound interest: Clara deposited CZK 100,000 in the bank with an annual interest rate of 1.5%. Both money and interest remain deposited in the bank. How many CZK will be in the bank after 3 years?
8. Bookshelve
Bookshelve with an original price of € 200 twice become cheaper. After the second discounted by 15% the price was € 149.60. Determine how much % become cheaper for the first time.
9. Simple interest 3
Find the simple interest if 11928 USD at 2% for 10 weeks.
10. Brunette
Of the girls who attend primary school are 30% blondes and 70% brunette. 81% blondes and 19% brunette has blue eyes. How many girls attending school altogether if 470 girls has blue eyes?
11. The deposit
Deposit has been placed for one year at an annual rate of 4.5%. After the added interst amount rose to € 2,612.5. Determine initial deposit.
12. Millionaire
Mr. Smith have gone withdraw from bank saving interest € 1,500. How big was his initial deposit if the annual interest rate is 1.5%?
13. 3 years savings
Simple interest - Tereza has deposited CZK 100,000 in the bank with an annual interest rate of 1.5%. Interest is added each year and left aside. How many CZK crowns will has total after 3 years?
14. Uranium ore
Uranium ore contains 0.2% of pure uranium and pure uranium contains 0.07% of fissile uranium. How many grams of fissile uranium contains 2800 ton of uranium ore?
15. Earth's surface
The greater part of the earth's surface (r = 6371 km) is covered by oceans; their area is approximately 71% of the Earth's surface. What is the approximate area of the land?
16. Salt
Sea water containing 5% salt. How many kg of fresh water necessary to pour into 40 kg of sea water so that the salinity fell to 2%?
17. Sugar
Sugar factory produced 127 tons of sugar in 1 day at 14% sugar content . How many tons of pure beet sugar factory processed in 1 day?
18. Percentage reduction
Reducing the unknown number by 19% get number 700.7 Determine unknown number.
19. Resort
In a completely crowded resort was 30% from the Czech Republic quarter visitors were from Slovakia and the rest 135 came from Germany. What capacity have resort?
20. Human buying irrationality
I longer watch processors for Socket A on ebay, Athlon XP 1.86GHz with a PR rating of 2500+ costs \$7 and Athlon XP 2.16Ghz with a PR rating of 3000+ currently cost \$16. Calculate: About what percentage of the Athlon XP 2.16Ghz is powerful than Athlon X

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