# Unknown number 5

Daniel think an integer. When he change this number at a ratio of 2:5 he got number 2.8. Determine what number think Daniel.

**Result****Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):**

**Showing 0 comments:**

**Be the first to comment!**

#### To solve this example are needed these knowledge from mathematics:

## Next similar examples:

- Diophantus

We know little about this Greek mathematician from Alexandria, except that he lived around 3rd century A.D. Thanks to an admirer of his, who described his life by means of an algebraic riddle, we know at least something about his life. Diophantus's youth l - Forestry workers

In the forest is employed 64 laborers planting trees in nurseries. For 8 hour work day would end job in 35 days. After 12 days, 20 laborers go forth. How many days is needed to complete a planting trees in nurseries by others, if they will work 9 hours a - Bonus

Gross wage was 1430 USD including 23% bonus. How many USD were bonuses? - Beer

After three 10° beers consumed in a short time there are 6.2 g of alcohol in 5 kg adult human blood. How much is it per mille? - Tape

Video is 153% more expensive than tape recorder. How many percent is tape recorder less expensive than video? - Motion problem

From Martina to Bratislavy go car at speed 76 km/h. From Bratislavy to Martina go another car at speed 53 km/h. How many minutes before the meeting will be cars 19 km away? - 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? - Motion2

Cyclist started out of town at 19 km/h. After 0.7 hours car started behind him in the same direction and caught up with him for 23 minutes. How fast and how long went car from the city to caught cyclist? - Logic

A man drinks a barrel of water for 39 days, woman for 64 days, for how many days they drink barrel together? - Hands

The clock shows 12 hours. After how many minutes will agle between hour and minute hand 90°? Consider the continuous movement of both hands hours. - Camp

In the camp are children. 1/2 went on a trip, 1/4 went to bathe and 58 children remained in the room. How many children are in camp? - Playing

How long have we trained on the pitch when we know that the warm-up took 10 minutes, we trained passes for one-third of the time and we played football half the time? - The sides

The sides of a rectangle are in a ratio of 2:3, and its perimeter is 1 1/4 inches. What are the lengths of its side? Draw it. - Car

Car goes from point A to point B at speed 86 km/h and back 53 km/h. If they goes there and back at speed 67 km/h trip would take 10 minutes shorter. What is distance between points A and B? - Garden

Father dig up the garden in 9 hours. Son in 13 hours. How many hours take dig up the garden together? - Alice

Alice spent 5/11 of her money on a back pack. She has $42 dollars left. How much was her back pack? - Trapezoid MO

The rectangular trapezoid ABCD with right angle at point B, |AC| = 12, |CD| = 8, diagonals are perpendicular to each other. Calculate the perimeter and area of the trapezoid.