How many four-digit numbers can you get out of
balls in the box:
of red ones and
of blue ones. In how many ways can two balls of the same color be picked?
In how many ways can you pick a captain and his deputy in a group of
cats. In how many ways he can take
of them in his hands (one - in left hand, another - in right)?
Three passengers walk into the elevator of the -floor building (ground floor is not included). In how many ways all three passengers can get out on different floors?
From the box in which there are
green balls, are randomly picked
. What is the probability that all three of them would be white?
The situation is the same as in the previous task. What is the probability of picking one white, one red and one green ball?
At the language school people can only study French, German or both. The event
happens when a random student decides to study French, the event
- when decides to study German. What is the probability when a randomly picked student decides to learn both languages(Event
There are red and
blue balls in the box. Event
happens when the first randomly picked ball is red. Event
happens when second randomly picked ball is also red. Calculate
An archer hits the target with the probability .
What is the probability that out of three shots he hits the target only the third time?