# Latest problems - page 11

- Father and son

When I was 11, my father was 35 years old. Today, my father has three times more years than me. How old is she? - Zdeněk

Zdeněk picked up 15 l of water from a 100-liter full-water barrel. Write a fraction of what part of Zdeněk's water he picked. - Toilets

A federal law requires that all residential toilets sold in the United States use no more than 1 3/5 gallons of water per flush. Prior to this legislation, conventional toilets used 3 2/5 gallons of water per flush. Find the amount of water saved in one ye - Volume of cone

Find the volume of a right circular cone-shaped building with a height of 9 cm and a radius base of 7 cm. - I think

I think a number. When I multiply it by five, and after that I subtract 477, I get the same number as if I multiplied it twice. What number do I think? - Twelve

Twelve students work on a week forestry brigade. One hundred spruces will receive x CZK, one hundred pine y CZK. How many receive each one students did in one day if they planted a total of 25,000 spruces per week and 30,000 pine trees? Express by expressi - Subsets

How many 19 element's subsets can be made from the 26 element set? - Raffle

There are 200 draws in the raffle, but only 20 of them win. What is the probability of at least 4 winnings for a group of people who have bought 5 tickets together? - Annual rainfall

The average annual rainfall is 686 mm. How many liters will fall on the 1-hectare field? - Bread to kilos

They brought in d two kilos and t three kilos of bread to the store. By the end of the day, 14 two-kg bread were sold. How many kilos of bread remained in the store by the next day? - Sum of squares

The sum of squares above the sides of the rectangular triangle is 900 cm^{2.}Calculate content of square over the triangle's hypotenuse. - Table

Find the circumference of the table, where the long side is 1.28 meters and the short side is 86 cm. - Fractions

Three-quarters of an unknown number are 4/5. What is 5/6 of this unknown number? - Bulb

A 60 W bulb consumes 0.12 kWh of electricity. How long did she stand light without a break? - Water tank

A 288 hectoliter of water was poured into the tank with dimensions 12 m and 6 m bottom and 2 m depth. What part of the volume of the tank water occupied? Calculate the surface of tank wetted with water. - Turners

Two turners perform joint work in 3 hours. The first turner would perform the job himself in 7 hours. How long would the same job last for a second turner if he worked alone? - Cinema tickets

Cinema sold 180 tickets this Thursday, which is 20%. Monday 14%, Tuesday 6%, Wednesday 9%, Friday 24%, Saturday 12%, and Sunday 15%. How many tickets were sold per week? - Babysitting

The amount that Susan charges per hour for babysitting are directly proportional to the number of children she is watching. She charges $4.50 for 3 kids. How much would she charge to babysit 5 kids? - Rectangle area

The length of a rectangle of x units is increased by 10% and its width of y units is increased by 15%. What is the ratio of the area of the old rectangle to the area if the new rectangle? - Mixture 2

How many liters of water must be added to 7 liters of a 20% solution to obtain a 10% solution?

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