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Discussion :: Time and Work

  1. A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :

  2. A.

    \( \frac { 1 } { 4 }\)

    B.

    \( \frac { 1 } { 10 }\)

    C.

    \( \frac {7} { 15 }\)

    D.

    \( \frac {8 } { 15 }\)

    View Answer

    Workspace

    Answer : Option D

    Explanation :

    A's 1 day's work =\( \frac { 1 } { 15 };\)

     

    B's 1 day's work =\( \frac { 1 } { 20 };\)

     

    (A + B)'s 1 day's work =\( [\frac { 1 } { 15 }+\)\( \frac { 1 } { 20 }]\)=\( \frac {7} { 60 }\)

     

    (A + B)'s 4 day's work =\([ \frac {7} { 60 }*4]\)=\( \frac {7} { 15 }\)

     

    Therefore, Remaining work =[1-\( \frac {7} { 15 }\)]=\( \frac {8 } { 15 }\)

     


Prasad khatua said : (Jun 10, 2021)

I am prepare for job


stephany Buckman said : (Jul 30, 2021)

Where from the 7/60 because I don't understand


Joel Kugonza said : (Jan 01, 2022)

How do they arrive to 7/60 in the first place


Mallikarjun potadar said : (Jan 20, 2022)

How do they substract 1-7/15


renuka said : (Jan 21, 2022)

why cant we take work done by A in 4 DAYS as 4/15 and work done by B in 4 days as 4/20 and add A'S work and B'S work AND THEN SUBTRACT (4/15+4/20 = 2/5) LEFT OVER WORK =1-2/5=3/5