Vempali Niranjan
Vempali Niranjan
8 years ago

A and B can complete a task in 30 days when working together. After A and B have been working together
for 11 days, B is called away and A himself completes the task in the next 28 days. Had A been working alone,
the number of days taken by him to complete the task would have been:

A. 44 4/9

B. 44

C. 343 4/9

D. 45


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Comments ( 3 )

  1. Binori Patra
    Binori Patra :
    6 years ago

    (A+B)*30=total work(Tw)
    (A+B)*11=11days work (11Dw)
    Tw-11Dw=remaining work
    (A+B)30-(A+B)11=(A+B)*19
    Given A complete (A+B)19 work in 28 days
    A*28=(A+B)*19
    28A=19B+19A
    9A=19B
    B=9/19A
    From above Tw =(A+B)*30
    =(A+9/19A)*30
    =28/19A*30
    =840/19 A
    We know Tw=efficiency *day
    A=efficiency of A
    Day = 840/19=44 and 4/19

  2. Nayan Bhuyan
    Nayan Bhuyan :
    6 years ago

    A and B can complete a task in 30 days when working together. So they perform 1/30 of the work in 1 day. After performing for 11 days, the amount of work already done becomes 11×1/30=11/30. Hence the amount of work left be 1-11/30=19/30.
    Now, A completes the left work in 28 days. This gives,
    19(X)/30 = 28
    => X = 28×30/19
    => X = 840/19
    => X = 44 and 4/19.
    Or, its nearest equivalent answer provided,
    44 4/9.

  3. Kumar Chandan
    Kumar Chandan :
    8 years ago

    A and B can complete the work in 30 days. So,
    Work Rate of A and B together = 100/30 = 3.33% per day.
    In 11 days, they have completed = 3.33 * 11= 36.63% of the work.
    Rest Work = 100 - 36.63 = 63.37%.
    63.37% work has been completed by A in 28 days. Thus,
    Work rate of A = 63.37/28 = 2.26% per day.

    Now, A alone can the entire work in = 100/2.26 = 44 . 24 days = 44 (4/9) days (Approx.)

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