How many arrangements of all the letters of the word are possible?
I. The word is APPLE.
II. The word has a repeated letter.
I: 5!/2! = 60. Sufficient.
II: CHERRY also repeats a letter but gives 360. Not sufficient.
Permutations and Combinations · Exercise 5 of 5
20 data sufficiency questions on permutations and combinations.
Directions: each question is followed by two statements. Decide whether the data in the statements is sufficient to answer the question, and choose the matching option.
How many arrangements of all the letters of the word are possible?
I. The word is APPLE.
II. The word has a repeated letter.
I: 5!/2! = 60. Sufficient.
II: CHERRY also repeats a letter but gives 360. Not sufficient.
In how many ways can the books be arranged on a shelf?
I. Some of them are maths books.
II. There are 3 different maths books and 2 different physics books, all to be shelved.
I: number of books unknown. Not sufficient.
II: 5 different books → 5! = 120. Sufficient.
How many players took part in the round-robin tournament?
I. 45 matches were played, each pair meeting once.
II. Each player played 9 matches.
I: nC2 = 45 → n = 10. Sufficient.
II: n − 1 = 9 → n = 10. Sufficient.
How many 4-letter codes can be made?
I. The letters are taken from A to F.
II. No letter may be repeated.
I alone: repeats allowed or not? Not sufficient.
II alone: alphabet unknown. Not sufficient.
Together: 6P4 = 360. Sufficient.
In how many ways can the prizes be given?
I. There are 3 prizes.
II. There are 5 students.
Each statement gives one number only. Not sufficient.
Together: whether the prizes differ and whether one student may win more than one is not stated (125, 60 or 35 ways). Not sufficient.
How many diagonals does the polygon have?
I. It is a hexagon.
II. It has more than 4 sides.
I: 6 × 3 ÷ 2 = 9. Sufficient.
II: 5, 6, 7 … sides all fit. Not sufficient.
How many arrangements can be made of the letters of a 4-letter word?
I. The word is TOOT.
II. The word is a palindrome made of two Ts and two Os.
I: 4!/(2! 2!) = 6. Sufficient.
II: TOOT or OTTO – the same letters, so 6 either way. Sufficient.
How many 3-member committees with at least one woman can be formed from a club?
I. The club has 4 women.
II. The club has 9 members.
I alone: men unknown. Not sufficient.
II alone: women unknown. Not sufficient.
Together: 9C3 − 5C3 = 84 − 10 = 74. Sufficient.
In how many ways can the group sit around a round table?
I. The number of people is even.
II. When everyone shook hands with everyone else once, there were 15 handshakes.
I: 4, 6, 8 … all even. Not sufficient.
II: nC2 = 15 → n = 6 → 5! = 120. Sufficient.
How many shortest street routes are there from A to B?
I. B is 3 blocks east of A.
II. B is 2 blocks north of A.
Each statement gives only one direction. Not sufficient.
Together: 5C2 = 10. Sufficient.
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