Permutation and Combination Questions for IBPS PO Pre 2018
Permutation and Combination Questions for Upcoming IBPS PO Pre 2018
Q1. The number of ways of arranging 6 persons in a row is
(a) 6!
(b) (–1)!
(c) 6
(d) 62
(e) None of these
Q2. How many words can be formed using all the letters of the word GINGER?
(a) 720
(b) 240
(c) 380
(d) 360
(e) None of these
Q3. The number of ways of selecting 4 members from a group of 10 members so that one particular member is always included is
(a) 63
(b) 72
(c) 84
(d) 56
(e) None of these
Q4. How many different words, which begin with N can be formed using all the letters of the word COUNTRY?
(a) 720
(b) 120
(c) 24
(d) 5040
(e) None of these
Q5. A bag contains 3 white balls, 4 green balls and 5 red balls. In how many ways two balls can be selected?
(a) 132
(b) 66
(c) 33
(d) 76
(e) None of these
Q6. How many three-digit numbers can be formed using the digits {1, 2, 3, 4, 5}, so that each digit is repeated any number of times?
(a) 150
(b) 200
(c) 25
(d) 125
(e) None of these
Q7. All possible four-digit numbers, with distinct digits are formed, using the digits {1, 3, 4, 5, 6}. How many of them are divisible by 5?
(a) 8
(b) 12
(c) 24
(d) 20
(e) None of these
Q8. In how many ways can 3 boys and 2 girls be seated in a row, so that all girls sit together?
(a) 12
(b) 24
(c) 84
(d) 48
(e) None of these
Q9. Ten points are selected on a plane, such that no three of them are collinear. How many different straight lines can be formed by joining these points?
(a) 54
(b) 45
(c) 90
(d) 108
(e) None of these
Q10. In how many ways can 5 men and 3 women be seated around a circular table?
(a) 720
(b) 5040
(c) 4020
(d) 2520
(e) None of these
Solutions
Ans.1(a)
We know that ‘n’ persons can be arranged in a row in n! ways here
n=6⇒∴the number of ways of arranging 6 members in a row=6!
Ans.2(d)
In the given word GINGER there are six letters in which G occurring two times ∴ the number of 6 letter words are 6!2!=360.
Ans.3(c)
Since on particular member is always included, we have to select 3 members from 9 members. This can be done in C3 9=84 ways.
Ans.4(a)
The word COUNTRY has 7 letters. Since the first letter is N, the remaining 6 places can be filled with 6 letters in 6! Ways.
The number of words that begin with N is 6! =720.
Ans.5(b)
The total number of balls in the bag is 3 + 4 + 5 = 12
Two balls can be selected from 12 balls in C2 12 or 12×112×1 =66 ways.
Ans.6(d)
Consider 3 blanks _ _ _
Since there are 5 digits, each blank can be filled in 5 ways.
Total number of ways is 5(5) (5) = 125.
Ans.7(c)
Consider four blanks
_ _ _ _
The units place is filled with 5. The remaining three blanks can be filled with 4 digits in P3 4 ways.
∴ The number of four-digit numbers required is 4 (3) (2) or 24.
Ans.8(d)
Treat all the girls as one unit. Now there are 3 boys and 1 unit of girls. They can be arranged in 4! Ways.
The two girls can be arranged among themselves in 2!ways.
Total number of arrangements 4!2! = 24(2) = 48.
Ans.9(b)
A straight line is formed by joining any two points.
Two points can be selected from 10 points in C2 10 or 10×92×1=45 ways.
Ans.10(b)
We know that n persons can be positioned around a circle in (n-1)! Ways.
∴ 8 persons can be arranged in 7! or 5040 ways.