SATHEE: Quantitative Aptitude Ques 2038

Quantitative Aptitude Ques 2038

Question: A man is twice as fast as a woman and a woman is twice as fast as a boy in doing a work. If all of them, a man, a woman and a boy can finish the work in 7 days, then how many days a boy will do it alone?

Options:

A) 49

B) 7

C) 6

D) 42

Show Answer

Answer:

Correct Answer: A

Solution:

Let the time taken by boy to complete the work $ =4x $ day Similarly, the time taken by woman to complete the work $ =2x $ days The time taken by man to complete the works $ =x $ days [ $ \because $ a woman is twice efficient than a boy and a man is twice efficient than woman] Now, together they can complete the work in 7 days.

$ \therefore $ One day’s work of all working together $ \frac{1}{4x}+\frac{1}{2x}+\frac{1}{x}=\frac{1}{7} $
$ \Rightarrow $ $ \frac{1+2+4}{4x}=\frac{1}{7} $

$ \Rightarrow $ $ \frac{7}{4x}=\frac{1}{7} $
$ \Rightarrow $ $ x=\frac{49}{4} $

$ \therefore $ A boy can finish the work $ =4x $ $ =4\times \frac{49}{4}=49days $

Quantitative Aptitude Ques 2037

Quantitative Aptitude Ques 2039

Quantitative Aptitude Ques 2038

Question: A man is twice as fast as a woman and a woman is twice as fast as a boy in doing a work. If all of them, a man, a woman and a boy can finish the work in 7 days, then how many days a boy will do it alone?

Options:

Answer:

Solution:

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