# Equation - 7th grade (12y) - examples - page 8

Two fifth-graders teams competing in math competitions - in Mathematical Olympiad and Pytagoriade. Of the 33 students competed in at least one of the contest 22 students. Students who competed only in Pytagoriade was twice more than those who just competed
2. Painting rooms
If Dano paint three hours daily given work he complete in 7.5 days. How many hours a day would have to work to finish the job 1.5 days earlier?
3. Workhorses
A team of colleagues done the work in 20 days. After adding 2 colleagues from the beginning the work was completed in 15 days. How many members has the colleague team?
4. TV commercials
For the typical one-hour prime-time television slot, the number of minutes of commercials is 3/8 of the minutes of the actual program. Determine how many minutes of the program are shown in that one hour.
5. Bases
The length of the bases trapezium are in ratio 4:5. Length of midline is 15. How long are the bases of a trapezoid?
6. Pocket
Mirka spent on a trip for gifts half pocket. For the third remain money bought a bagel. Six euros left her. How many euros had Mirka in pocket?
7. Pool 2
The first supply by the pool fill for five hours and the second fill for six hours, drain should be drained for 15 hours. For how many hours the pool is full, when we open both inlet now and outlet open two hours later?
8. Coffee
Coffee from the machine in the cup cost 28 cents. Coffee is 20 cents more expensive than the cup. How much is the cup?
9. Trousers
Jarek bought new trousers, but the trousers were too long. Their length was in the ratio 5: 8 to Jarek height. Mother his trousers cut by 4 cm, thus the original ratio decreased by 4%. Determine Jarek's high.
10. Salary
Mr. Johnson's had monthly salary 955 USD since the beginning of year. From which month his salary was increased by 52 USD, when in year earned 11824 USD (enter as a number from 1 to 12)?
11. Secret number
Determine the secret number n, which reversed decrease by 16.4 if the number increase by 16.4.
12. Bicycles
You're the owner of the transport 's learning playground. Buy bicycles of two colors but you've got to spend accurately 120000 Kč. Blue bike costs 3600Kč and red bicycle 3200Kč.
13. Equation with fractions
Solve equation: ? It is equation with fractions.
14. Square Number
If to a square of integer number add 31, we get the square of next integer number. What is the original number?
15. Guess number
With what number should be divided number 9727 to be reduced by 70%?
16. Ski lessons
On the ski course leaves 80 pupils. They live in triple and quadruple rooms. Count if rooms is the 23. How many are triple and quadruple rooms?
17. Product
The sum and the product of three integers is 6. Write largest of them.
18. Tetrahedral prism
The height of a regular tetrahedral prism is three times greater than the length of the base edge. Calculate the length of the base edge, if you know that the prism volume is 2187 cm3.
19. Stairs
Between adjacent levels are 15 stairs. If step will be 1.2 cm lower there would be 16 stairs. What is the stair height?
20. Bank deposit
Ms Jana after the withdraw amount of 2,500 euros after year saving in bank. What was her deposit if the interest rate was 2.5% p.a..

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