# Equation - examples - page 24

1. Workers 2
Worker dug the trench for 7 hours, another worker for 10 hours. They recruited to work even one worker more. Digging should be done for 2 hours. For how long would dig third worker alone?
2. Classroom
In a classroom are 30 students, boys are four times more than girls. How many boys are in the class?
3. Isosceles trapezoid
Calculate the content of an isosceles trapezoid whose bases are at ratio 5:3, the arm is 6cm long and it is 4cm high.
4. On the farm
On the farm were housed 70 heads of cattle with food supply for 180 days. After 60 days, 10 head of cattle sold, and for the next 30 days they sold 10 more. How many days is sufficient supply of feed for the remaining cattle?
5. Classroom
In a class are 32 pupils. Boys are 8 less than girls. How many boys and girls are in the classroom?
6. 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%?
Daddy is a 46 year old and son is at age of 16. When (which year) was/will daddy 5 times more years than his son?
8. Calcium and citality
The daily dose of calcium obtained using 0.75 liters of milk and 60 grams of cheese. A/ At the morning I drank half a liter of milk. How much cheese I must eatto eat a daily dose of calcium? b / I ate 50 grams of cheese, how much milk I must drink? c /.
9. Supplementary angles
One of the supplementary angles are three times larger than the other. What size is larger of supplementary angles?
10. The book
If one day you read p pages, you will read the book 24 days. If you read each day 10 pages more, you would read a book in 16 days. How many pages have the book?
11. Trapezoid
How long are the trapezoid bases with area 24 cm2 and height 3 cm. One base is 3 times longer than the shorter.
12. 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?
13. 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%?
14. 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?
15. Translations
If I going to translate the book 6 pages per day I translate it 4 days earlier than if I translated 5 pages a day. If I translate 4 pages a day I translate it for how many days.....?
16. Mason with assistant
Mason had to complete the work in 10 days. Two and a half days later his assistant arrived. Together they completed the work in next three and a half days. How many days would he need an assistant for the same work?
17. Float boya
A 0.5 meter spherical float is used as a location mark for a fishing boat anchor. It floats in salt water. Find the depth to which the float sinks if the material of which the float is made weighs 8 kilograms per cubic meter and salt water weighs 1027 kg/m
18. Work at plant
Handyman has vowed to do repair work at the plant for 25 days. However, work had to be shortened and therefore gained helper. Together they made all the corrections for 13 1/3 days. How long the work would take helper himself?
19. Rabbit family
Rabbit family ate 32 pieces of carrots, small one ate 6 pieces, dad 5 more than the mother. How much ate mom?
20. Percentage reduction
Reducing the unknown number by 19% get number 700.7 Determine unknown number.

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