Latest TCS Aptitude Question SOLUTION: in how many ways can he letters of the english alphabet be arranged so that there are seven letters between the letters a and b and no letter is repeated a)36*24! b18*24! c)24P7*2

• Placement Papers
• /
• TCS
• /
• Numerical Ability
• /
• Permutation and Combination

TCS Question Papers: TCS Interview Experience(90) TCS Company Profile

(#M40115062) TCS Numerical Ability question permutation and combination Keep an EYE

in how many ways can he letters of the english alphabet be arranged so that there are seven letters between the letters a and b and no letter is repeated

a)36*24!
b18*24!
c)24P7*2*18!
d)24P7*3*18!

Asked In TCS Divya jain (9 years ago)

Unsolved Read Solution (6)

Is this Puzzle helpful?   (11)   (1) Submit Your Solution Permutation and Combination

Read Solution (6) :

Surit Datta  (9 years ago)

A -B or B - A --------------------> 2 WAYS
from rest 24 letters, 7 can be arranged in 24P7 = 24! ways
also position of A-------B can be 1-------9, 2--------10, ..., 18-------26 ( 18 ways )
total no. of ways = 24P7 * 2 * 18! ways.

Is this solution Helpfull? Yes (29) | No (5)  

ishan chourishi  (8 years ago)

answer is a) 36*24!
let us ignore a and b so there will be 24! ways of arranging.
now consider a - - - - - - - b as one and other 17 alphabets so its will be 18.
we can also arrange a and b in 2! ways.
so final answer will be : 24!*18*2= 24!*36.

Is this solution Helpfull? Yes (2) | No   

Pallavi Verma  (9 years ago)

@ ANIBRATA HARI if a is at pos 1 b will at pos 9 and vice versa
again if a is at 2 then b will ai pos 10
3......................11
4......................12
5......................13
6......................14
7......................15
like this when we reach 18 th pos if a is at 18 b will be at 26
and 26 is our limit..........
so,there are 18 ways again a and b can exchange position then 18*2 ways............and then *24P7 because 2 alphabets are used we are left with 24 and 7 position are there so 24P7

Is this solution Helpfull? Yes (1) | No   

Anibrata Hari  (9 years ago)

can anyone explain how r these 18 ways r forming

Is this solution Helpfull? Yes | No   

neha agarwal  (9 years ago)

its coming 17! instead of 18! ?

Is this solution Helpfull? Yes | No (1)  

Mahima   (9 years ago)

13. A permutation is often represented by the cycles it has. For example, if we permute the numbers in the natural order to 2 3 1 5 4, this is represented as (1 3 2) (5 4). In this the (132) says that the first number has gone to the position 3, the third number has gone to the position 2, and the second number has gone to position 1, and (5 4) means that the fifth number has gone to position 4 and the fourth number has gone to position 5. The numbers with brackets are to be read cyclically. If a number has not changed position, it is kept as a single cycle. Thus 5 2 1 3 4 is represented as (1345)(2). We may apply permutations on itself If we apply the permutation (132)(54) once, we get 2 3 1 5 4. If we apply it again, we get 3 1 2 4 5 , or (1 2 3)(4) (5) If we consider the permutation of 7 numbers (1457)(263), what is its order (how many
7541263
3467152
2653741
2542367.....
.
;
7541263
in 12th permutation

Is this solution Helpfull? Yes | No (1)  

Please Login to Read Solution.