# Examples for 8th grade - page 115

1. Pages counting There are pages numbered from 2 to 104 in the book. How many digits have to be printed to number the pages?
2. Pile of sand A large pile of sand has been dumped into a conical pile in a warehouse. The slant height of the pile is 20 feet. The diameter of the base of the sand pile is 31 feet. Find the volume of the pile of sand.
3. Jane plants Jane plants flowers in the garden. If she planted 12 every hour instead of 9 flowers, she would finish with the job an hour earlier. How many flowers does she plant?
4. Odd/even number Pick any number. If that number is even, divide it by 2. If it's odd, multiply it by 3 and add 1. Now repeat the process with your new number. If you keep going, you'll eventually end up at 1. Every time. Prove. ..
5. Simplify Simplify expression - which expression is equivalent to: 3(m + 2) − 4(2m − 9)
6. Boats Three-quarters of boats are white, 1/7 are blue and 9 are red. How many boats do we have?
7. Screens The area of a 25 inch TV screen is 300 inch² the area of a 40 inch TV screen is 768 inch². The area of the smaller screen is what percent of the area of the larger screen?
8. Perctentages 35% of what number is 35?
9. Air thermal Imagine that a unit of air rises at 3000 meters high, if temperature decreases 6 degrees celcius for every 1000 meter, what will be its temperature at 1400 meters, 2000 meters, 2500 meters and when it reaches the 3000 meter elevation. Starting temperature.
10. The publisher The publisher prepares the release of the dictionary. Print preparation costs no matter the number of printed copies of 150000 CZK. The printer charges 80 CZK for one print. A) What are the costs of one dictionary if 5000 copies printed? B) For what numb
11. Triangle 42 Triangle BCA. Angles A=119° B=(3y+14) C=4y. What is measure of triangle BCA=?
12. MG=7x-15, MG=7x-15, FG=33, x=? Point M is the midpoint of FG. Find unknown x.
13. Find the 7 Find the number that is smaller than 5 5/12 by as much as 2 2/13 is smaller than 6 1/6
14. Two numbers 7 The sum of two consecutive even numbers is 30. Find the numbers.
15. Evening shift While working the evening shift, Officer K took 8 hours to complete a task at his work station and Officer M took 10 hours to complete the same task at his work station. How many hours would it take Officer K and Officer M to complete the same task working
16. Simple equation 6 Solve equation with one variable: X/2+X/3+X/4=X+4
17. Toys 3 Tiffany's toyshop received a shipment of 360 toys. The first day 12 were sold the second day 19 were sold and on the third day, 26 was sold. How many days will the toyshop run out of toys?
18. Eq with reciprocal Solve given equation with reciprocal member: a-6/a+10=4/8
19. Round-trip A woman works at a law firm in city A which is about 50 miles from city B. She must go to the law library in city B to get a document. Find how long it takes her to drive​ round-trip if she averages 40 mph.
20. Ping time Calculate theoretical ping time between Orlando and Shenzhen which is 14102 km distant. Ping time measures the round-trip time for small messages sent from the origin to a destination that is echoed back to the source. The name comes from active sonar term

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