Sawaal
18
Q:

Find the number of ways in which 21 balls can be distributed among 3 persons such that each person does not receive less than 5 balls.

A) 28 B) 14
C) 21 D) 7

Answer:   A) 28



Explanation:

Let x, y, z be the number of balls received by the three persons, then

  

x≥5, y≥5, z≥5 and x+y+z=21

 

Let u≥0, v≥0, w≥0 then

 

∴ x + y + z =21

 

⇒ u + 5 + v + 5 + w + 5 = 21

 

⇒ u + v + w = 6 

 

∴Total number of solutions = C3-16+3-1=C28=28

Subject: Permutations and Combinations - Quantitative Aptitude - Arithmetic Ability
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A) 3 B) 4
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Answer & Explanation Answer: A) 3

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In a bag containing red, green and pink tokens, the ratio of red to green tokens was 5 : 12 while the ratio of pink to red tokens was 7 : 15. What was the ratio of green to pink tokens?

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The ratio of the members of blue to red balls in abag is constant. When there were 44 red balls, the number of blue balls was 36. If the number of blue balls is 54, how many red balls will be in the bag?

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Answer & Explanation Answer: D) 66

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If each vowel of the word NICELY is changed to the next letter in the English alphabetical series and each consonant is changed to the previous letter in the English alphabetical series and then the alphabets are arranged in alphabetical order, which of the following will be fourth from the left?

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Answer & Explanation Answer:

Explanation:

Thus after arranging the letters as per English alphabetical series; we get; Thus 4th letter from the left end will be K.

 

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Explanation:

Hence there are two pairs.

 

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