# Doubling

The message is spreading that each day has doubled the number of people who know about it. All know message for 20 days. How long known it eighth people?

**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:

- Midnight

How many hours are, if the time that elapsed since 8:00 is 2/5 of the time that will past till midnight? - Suzan

My daughter reaches X years in X squared, said Suzan father in 2009 during the celebration of her birthday. When will given fact become reality and how many years at that time will have Suzan? - The dice

What is the probability of events that if we throw a dice is rolled less than 6? - Mr and Mrs

Mr. Calda and Mrs. Cald have a total of 139 years. How many years have when we know that Mr. Calda is 9 years older than Mrs. Cald - Pupils

Four pupils is going via dark hall. Start at one side and have to get to the other side for 17 minutes. They have only one lamp for the trip. The corridor is narrow, they can therefore go up two pupils at a time and go at the slower speed. Each pupil went. - Candies

If Alena give Lenka 3 candy will still have 1 more candy. If Lenka give Alena 1 candy Alena will hame twice more than Lenka. How many candies have each of them? - Theorem prove

We want to prove the sentense: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started? - On a farm

On a farm, there are 90 rabbits, 700 sheep, 300 cattle and 500 pigs. What percentage of the total number of animals are rabbits? - Basket of fruit

In six baskets, the seller has fruit. In individual baskets, there are only apples or just pears with the following number of fruits: 5,6,12,14,23 and 29. "If I sell this basket," the salesman thinks, "then I will have just as many apples as a pear." Which - One half

One half of ? is: ? - Powers

Express the expression ? as the n-th power of the base 10. - Mother and daughter

The mother is four times older than her daughter. Five years ago, her daughter was seven times younger than her mother. How many years do they have now? - Adam and Ben

When Ben is so many years old to Adam today, Adam will be 23 years old. When Adam was as old as Ben, Ben was two years old. How old is today Ben and Adam? - 5 pumps

Five pump to pump 3 hours 1600 hl of water. How long pumped same amount of water 4 pumps? - Workers

Group of workers washing half of the windows of the building in two hours. How long will take half the workers wash all the windows of the building? - Antennas

If you give me two antennas will be same. If you give me again your two antenna I have a 5× so many than you. How many antennas have both mans? - Family

Mom is 42 years old and her daughters 13 and 19. After how many years will mother as old as her daughter together?