Themes, topics - practice for 14 year olds
Number of problems found: 1358
- Two persons
Two persons are walking beside a railway track at respective speeds of 2 and 4 km per hour in the same direction. A train came from behind them and crossed them in 90 and 100 seconds, respectively. Find the length of the train. - 20 men
20 men are supposed to complete a work in 10 days. After working for 5 days, they realize that only one-fourth of the work is done. How many more men they need to employ to complete the work on time? - Taps and a tank
A tap can fill a tank in 6 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely? - Manday, manhour
Job problem: 10 men can make 20 toys in 12 days working 12 hours a day.Then, in how many days can 24 persons make 32 toys working 16 hours a day?
- Solution dilution
I'm further diluting a solution which has previously been diluted. I started with a 1:4 dilution, then diluted that a further 1:5, what is my dilution factor after this? - A park on map
A park has an area of ⅙ mi². On a map, the park has an area of 1 ¼ cm². On the map, how many square centimeters represent 1 mi²? - Hoverboard
Adam lives in Podhradí, and his friend Marcel lives in Lhota. Lhota is 6 km from Podhradí. Adam travels the same distance on a hoverboard in 20 minutes as Marcel does in 25 minutes. They leave home simultaneously, drive towards each other, and meet in pre - Working together
Zeru can complete a certain job in 5 days, and Tulu can complete the same job in 3 days. How long will they complete the job if they work together? - Two containers 2
Two containers, one large and one small, contain a total of 4 kilograms of bath salts. One-quarter of the bath salts from the large container are transferred to the small container, so the ratio of bath salts in the large container to that in the small on
- RST triangle
Find out if it is possible to construct the given triangle and according to which theorem: RS = 2.5 cm ST = 7 cm TR = 4.5 cm - The sum 41
The sum of 640.00 was deposited in the first bank for five years, and the interest given was 160.00. Find the rate. - And - or probability rules
Given P(A)=0.4, P(B)=0.56, and P(A and B)=0.274, find the value of P(A or B), rounding, if necessary. - Ekene and Amina
The probability that Ekene will be alive in 5 years' time is 3/4, and the probability that his wife Amina will be alive in 5 years' time is 2/5. Find the probability that in 5 years' time: a) both of them will be alive b) only Ekene will be alive - 2-cycle
2-cycle engines require a mixture of oil and gas to run properly. For every gallon of gas, a certain 2-cycle engine requires 1 1/4 fl oz of oil. How much oil must be added to prepare 3 1/2 gallons of gas to get the proper mixture?
- A chemist 2
A chemist has two alloys of bronze, one that is 12% tin and 88% copper and a second that is 10% tin and 90% copper. If these two alloys are melted and thoroughly mixed together, between what two values are the percent of tin in the mixture? - Bank deposits
At the end of each quarter, Patti deposits $1,400 into an account that pays 10% interest compounded quarterly. How much will Patti have in the account in three years? Note: Use tables, Excel, or a financial calculator round your final answer to the neares - Heat energy
Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1°C, 4200 J of heat energy is required. (a) Kelly wants to increase the temperature of 2 liters of w - Dinesh 2
Dinesh left town L for town M at a constant speed and took 10 hours to complete the journey. At the same time, Saanvi left town M for town L, traveled at a constant speed, and took 6 hours to complete the journey. They both passed each other at a point 72 - Map scale
On a map, on a scale of 1:50000, what is the distance in kilometers that 6 cm on the map represents?
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