Permutations & Combinations
Important Instructions
On a railway line there are 20 stops. A ticket is needed to travel between any 2 stops. How many different tickets would the government need to prepare to cater to all possibilities?
Answer: C
No answer description available for this question.
Enter details here
How many four digit numbers can be formed using the digits {1, 3, 4, 5, 7,9}(repetition of digits is not allowed)?
Answer: A
No answer description available for this question.
Enter details here
There are 18 stations between Hyderabad and Bangalore. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station?
Answer: D
No answer description available for this question.
Enter details here
There are 30 people in a group. If all shake hands with one another , how many handshakes are possible?
Answer: B
No answer description available for this question.
Enter details here
A box contains 2 white balls, 3 black balls and 4 red balls. In how many ways can 3 balls be drawn from the box, if at least one black ball is to be included in the draw?
Answer: C
No answer description available for this question.
Enter details here
How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9, which are divisible by 5 and none of the digits is repeated?
Answer: D
Since each desired number is divisible by 5, so we must have 5 at the unit place. So, there is 1 way of doing it.
The tens place can now be filled by any of the remaining 5 digits (2, 3, 6, 7, 9). So, there are 5 ways of filling the tens place.
The hundreds place can now be filled by any of the remaining 4 digits. So, there are 4 ways of filling it.
Required number of numbers = (1 x 5 x 4) = 20.
Enter details here
In how many different ways can the letters of the word 'CORPORATION' be arranged so that the vowels always come together?
Answer: D
No answer description available for this question.
Enter details here
There are 8 routes from London to Delhi. And there are 6 routes from Delhi to Tokyo. In how many different ways can Raj travel from London to Tokyo via Delhi?
Answer: B
No answer description available for this question.
Enter details here
A question paper had 10 questions. Each question could only be answered as true(T) of False(F). Each candidate answered all the questions, Yet no two candidates wrote the answers in an identical sequence. How many different sequences of answers are possible?
Answer: D
No answer description available for this question.
Enter details here
In a class, there are 15 students. During a Christmas party all of them shook hands with each other only once. How many handshakes took place in the class?
Answer: C
No answer description available for this question.
Enter details here