Themes, topics - practice for 13 year olds - page 81 of 82
Number of problems found: 1639
- Tanker
The first pump can empty an oil tanker in 4.9 hour. The second pump can empty a tanker in 8 hours. If the first pump started at 4:00 and the second 1.4 hour later, at what time will the tanker be empty? - Sea water
Seawater contains about 5% salt. How many dm³ of distilled water must we pour into 39 dm³ of seawater to get water with 1.6% salt? - Steamship
Between the two ports on the river is going steamship. The journey there and back takes 8:42. Downstream steamship traveling at 20 km/h, upstream 9 km/h. What is the distance between the ports? - Workers
Two workers would fulfill a certain task when working together for 5 days, the first if he worked himself done work in 13 days. How many days will the second worker do the whole job?
- Drinking water
A man drinks a keg of water in 36 days, and a woman drinks in 65 days. How many days do they consume a keg together? - Forestry workers
56 laborers have employed planted trees in the forest. For 8 hour work, a day would end job in 37 days. After 16 days, 9 laborers go forth? How many days are needed to complete planting trees in nurseries by others if they work 10 hours a day? - Two cars
Two cars started against each other simultaneously to journey long 346 km. The first car went 53 km/h and the second 53 km/h. What distance will be between these cars 20 minutes before a meeting? - Bus vs. train
The bus started from point A 10 minutes before the train started from the same place. The bus went at an average speed of 49 km/h, train at 77 km/h. To point B train and bus arrived simultaneously. Calculate the train journey time if the train and bus tra - Truck
The truck went for 4 hours and 51 minutes. If the truck increases its speed by 23 km/h, it will go the same distance in 2 hours. Calculate this distance.
- Scale
The swimming pool is long 110 m and 30 m wide. The city's plan is shown as a rectangle with an area 8.25 cm². What scale is the city plan? - Alcohol
How much 56% alcohol do we need to pour into 22 liters 78% alcohol to get p3% alcohol? How much 76% alcohol do we get? - Short cut
Imagine that you are going to a friend. That path has a length 120 meters. Then turn doprava and go other 630 meters, and you are at a friend's. The question is, how much will the journey be shorter if you go direct across the field? - Sea water
Mixing 62 kg of seawater with 84 kg rainwater is created water containing 3.1% salt. How much percent of seawater contains salt? - Coffee
In-stock are three kinds of branded coffee prices: I. Kind. .. .. .205 Kc/kg II. Kind. .. .. .274 Kc/kg III. Kind. .. .. 168 Kc/kg Mixing these three species in the ratio 8:5:6 create a mixture. What will be the price of 100 grams of this mixture?
- 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? - Trains for people
It is said that the train is synonymous to delay. Calculate the average travel speed by train long 85 km, with a regular train leaving at 7:00 and arriving at 8:18, but the train is late and has a departure at 8:10 and arrives at 9:27. - Motion
From two different locations, distant 232 km started against car and bus. The car started at 7:10 with an average speed of 74 km/h. The bus started at 8:40 with an average speed of 48 km/h. When did they meet? How many kilometers went the bus? - Vinegar
We must dilute 16 liters of 8.8% aqueous vinegar to 4.1% one. How much water is necessary to add? - Proof PT
Can you easily prove Pythagoras' theorem using Euclidean theorems? If so, do it.
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