1) During the latest round of the BrainBashers triathlon, Keith was fourth. Adrian is not the oldest, but is older than Duncan, who was not second. The child who was next in age to the youngest, finished second. The child who finished in third place is older than the child who finished first. Billy is younger than the child who finished in third place. Can you determine who finished where and place the children in order of age?
2)
Among the families with two children, which have at least one boy, what is the probability that the family has two boys? €‹
A line of 100 airline passengers is waiting to board a plane. They each hold a ticket to one of the 100 seats on that flight. (For convenience, let's say that the nth passenger in line has a ticket for the seat number n.) Unfortunately, the first person in line is crazy, and will ignore the seat number on their ticket, picking a random seat to occupy. All of the other passengers are quite normal, and will go to their proper seat unless it is already occupied. If it is occupied, they will then find a free seat to sit in, at random. What is the probability that the last (100th) person to board the plane will sit in their proper seat (#100)?
10 different letters of alphabet are given . words with 5 letters are formed from these letters. The no of words which have at least one letter repeated is_____- ans: 69760 kindly explain
Ram is very tall and so, he can climb 1, 2 or 3 steps of a certain staircase at a time. In how many different ways can he climb the staircase if it has 10 steps?
(Note that climbing 2 steps first and 1 step later is a different case from climbing 1 step first and 2 steps later)
There are 3 piles of stone . pile 1st contains 1 stone, pile 2nd contains 2 stones and pile 3rd contains 3 stone.there is 2 players A and B. Game is as following.A and B has to pick stone alternatively. one can either pick the topmost stone or has to pick the whole pile. A plays first. The person who pick the last stone losses. How A can play the game so that he always win?
The number lock of a suitcase has 4 wheels, each labelled with ten digits i.e., from 0 to 9. The lock opens with a sequence of four digits with no repeats. What is the probability of a person getting the right sequence to open the suitcase?
