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Q:

# How many lines can you draw using 3 non collinear (not in a single line) points A, B and C on a plane?

 A) 3 B) 6 C) 2 D) 4

Answer:   A) 3

Explanation:

You need two points to draw a line. The order is not important. Line AB is the same as line BA. The problem is to select 2 points out of 3 to draw different lines. If we proceed as we did with permutations, we get the following pairs of points to draw lines.

AB , AC

BA , BC

CA , CB

There is a problem: line AB is the same as line BA, same for lines AC and CA and BC and CB.

The lines are: AB, BC and AC ; 3 lines only.

So in fact we can draw 3 lines and not 6 and that's because in this problem the order of the points A, B and C is not important.

Q:

From a group of 7 boys and 6 girls, five persons are to be selected to form a team, so that at least 3 girls are there in the team. In how many ways can it be done?

 A) 427 B) 531 C) 651 D) 714

Answer & Explanation Answer: B) 531

Explanation:

Given in the question that, there are 7 boys and 6 girls.

Team members = 5

Now, required number of ways in which a team of 5 having atleast 3 girls in the team =

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2 142
Q:

The number of ways in which 8 distinct toys can be distributed among 5 children?

 A) 5P8 B) 5^8 C) 8P5 D) 8^5

Answer & Explanation Answer: B) 5^8

Explanation:

As the toys are distinct and not identical,

For each of the 8 toys, we have three choices as to which child will receive the toy. Therefore, there are ${\mathbf{5}}^{\mathbf{8}}$ ways to distribute the toys.

Hence, it is ${\mathbf{5}}^{\mathbf{8}}$ and not ${\mathbf{8}}^{\mathbf{5}}$.

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1 661
Q:

In how many different ways can the letters of the word 'THERAPY' be arranged so that the vowels never come together?

 A) 1440 B) 720 C) 2250 D) 3600

Answer & Explanation Answer: D) 3600

Explanation:

Given word is THERAPY.

Number of letters in the given word = 7

These 7 letters can be arranged in 7! ways.

Number of vowels in the given word = 2 (E, A)

The number of ways of arrangement in which vowels come together is 6! x 2! ways

Hence, the required number of ways can the letters of the word 'THERAPY' be arranged so that the vowels never come together = 7! - (6! x 2!) ways = 5040 - 1440 = 3600 ways.

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1 395
Q:

In how many different ways can the letters of the word 'HAPPYHOLI' be arranged?

 A) 89,972 B) 90,720 C) 72,000 D) 81,000

Answer & Explanation Answer: B) 90,720

Explanation:

The given word HAPPYHOLI has 9 letters

These 9 letters can e arranged in 9! ways.

But here in the given word letters H & P are repeated twice each

Therefore, Number of ways these 9 letters can be arranged is

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5 536
Q:

How many words can be formed with or without meaning by using three letters out of k, l, m, n, o without repetition of alphabets.

 A) 60 B) 120 C) 240 D) 30

Answer & Explanation Answer: A) 60

Explanation:

Given letters are k, l, m, n, o = 5

number of letters to be in the words = 3

Total number of words that can be formed from these 5 letters taken 3 at a time without repetation of letters =

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7 523
Q:

The letters of the word PROMISE are to be arranged so that three vowels should not come together. Find the number of ways of arrangements?

 A) 4320 B) 4694 C) 4957 D) 4871

Answer & Explanation Answer: A) 4320

Explanation:

Given Word is PROMISE.

Number of letters in the word PROMISE = 7

Number of ways 7 letters can be arranged = 7! ways

Number of Vowels in word PROMISE = 3 (O, I, E)

Number of ways the vowels can be arranged that 3 Vowels come together = 5! x 3! ways

Now, the number of ways of arrangements so that three vowels should not come together

= 7! - (5! x 3!) ways = 5040 - 720 = 4320.

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7 982
Q:

In how many different ways can the letters of the word 'POVERTY' be arranged ?

 A) 2520 B) 5040 C) 1260 D) None

Answer & Explanation Answer: B) 5040

Explanation:

The 7 letters word 'POVERTY' be arranged in $\mathbf{7}{\mathbit{P}}_{\mathbf{7}}$ ways = 7! = 5040 ways.

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12 583
Q:

A decision committee of 5 members is to be formed out of 4 Actors, 3 Directors and 2 Producers. In how many ways a committee of 2 Actors, 2 Directors and 1 Producer can be formed ?

 A) 18 B) 24 C) 36 D) 32

Answer & Explanation Answer: C) 36

Explanation:

Required Number of ways = = 36

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17 650