SSC Quantitative Aptitude Time And Work Question Bank Work and Time (II)

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, in how many days a boy will do it alone? [SSC CGL Tier II, 2014]

A) 49

B) 7

C) 6

D) 42

Correct Answer: A

Solution :

[a] 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 work \[=x\] days [\[\therefore \]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. So, \[\frac{1}{4x}+\frac{1}{2x}+\frac{1}{x}=\frac{1}{7}\] [One day's work of all working together] \[\frac{1+2+4}{4x}=\frac{1}{7};\frac{7}{4x}=\frac{1}{7}\] \[\Rightarrow \] \[x=\frac{49}{4}\] \[\therefore \]A boy can finish the work in \[4\times \frac{49}{4}=49\]days

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SSC Quantitative Aptitude Time And Work Question Bank Work and Time (II)

question_answer 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, in how many days a boy will do it alone? [SSC CGL Tier II, 2014] A) 49 B) 7 C) 6 D) 42

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, in how many days a boy will do it alone? [SSC CGL Tier II, 2014]

A) 49

B) 7

C) 6

D) 42