# Equation - 8th grade (13y) - examples

- Sales off

The price has decreased by 20%. How many percents do I have to raise the new price to be the same as before the cut? - Acid evaporation

How many kilograms of water do we have to evaporate from 100 kg of 32% acid to make it 80% concentration? - Father and daughter

When I was 11 my father was 35 year old. Now, father has three times older then me. How old is she? - Granules

Katy had two dogs. The first one ate a pack of granules a week and the other two times longer. Katka bought them two bags of granules. How long does it last for both dogs? - Pupils

There are 350 girls in the school, and the other 30% of the total number of pupils are boys. How many pupils does the school have? - Equation - inverse

Solve for x: 7: x = 14: 1000 - Two pipes

How long will the pool be filled with a double supply pipe if it takes the pool to fill the first pipe by 4 hours longer and the second pipe 9 hours longer than both pipes open at the same time? - Simple equation 6

Solve equation with one variable: X/2+X/3+X/4=X+4 - Two friends

Peter can do all his work himself in 6 hours. Martin can do the same work himself in 8 hours. Peter worked first and then replaced by Martin. Whole work was done in 6.5 hours. Calculate how long Peter worked before replaced by Martin. - Marriage sttus

In our city, there are 3/5 of the women married to 2/3 of the men. Find what part of the population is free. - Mushrooms

Fresh mushrooms contain 88% water, dried 14% water. How many kilograms of fresh mushrooms should be collected to get 3 kg of dried? - Garden

Area of square garden is 6/4 of triangle garden with sides 56 m, 35 m and 35 m. How many meters of fencing need to fence a square garden? - Pool

If water flows into the pool by two inlets, fill the whole for 18 hours. First inlet filled pool 6 hour longer than second. How long pool is filled with two inlets separately? - Forestry workers

In the forest is employed 56 laborers planting trees in nurseries. For 8 hour work day would end job in 37 days. After 16 days, 9 laborers go forth? How many days is needed to complete planting trees in nurseries by others, if they will work 10 hours a da - Bonus

Gross wage was 527 EUR including 16% bonus. How many EUR were bonuses? - Right Δ

Right triangle has length of one leg 28 cm and length of the hypotenuse 53 cm. Calculate the height of the triangle. - Troops

Route is long 147 km and the first day first regiment went at an average speed 12 km/h and journey back 21 km/h. The second day went second regiment same route at an average speed 22 km/h there and back. Which regiment will take route longer? - Motion problem

From Levíc to Košíc go car at speed 81 km/h. From Košíc to Levíc go another car at speed 69 km/h. How many minutes before the meeting will be cars 27 km away? - Excavation

Mr. Billy calculated that excavation for a water connection dig for 12 days. His friend would take 10 days. Billy worked 3 days alone. Then his friend came to help and started on the other end. On what day since the beginning of excavation they met? - Logic

A man drinks a barrel of water for 26 days, woman for 48 days, for how many days they drink barrel together?

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