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Quiz: Time & Work

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Number of Questions: 31

Question: 26 -

A and B can do a piece of work in 12 days. B and C can do it the same work in 20 days. In how many days will A, B and C finishes it working all together? Also, find the number of days taken by each to finish it working alone?

Options:

  1.  Together=10 days,
     A=30 days,
     B=20 days,
     C=60 days 

  2. Together=20 days,
    A=30 days,
    B=20 days,
    C=50 days

  3. Together=15 days,
    A=300 days,
    B=20 days,
    C=60 days

  4. Together=10 days,
    A=20 days,
    B=30 days,
    C=60 days

    5. Answer:

     Together=10 days,
     A=30 days,
     B=20 days,
     C=60 days 
    Solution:

    Given (A+B)s one days work=1/12 ---- (1)
    (B+C)s one days work=1/15 ------- (2)
    and (A+C)s one days work=1/20. -------- (3)
    By eq. 1, 2 and 3 
    2(A+B+C)s one days work = (1/12+1/15+1/20)=1/5.
    => (A+B+C)s one days work=1/10.
    => A, B and C together can finish the work in 10 days.
    Now, As one days work 
    = [(A+B+C)s one days work (B+C)s one days work]
    = 1/10-1/15)
    = 1/30.
    Therefore, A alone can finish the work in 30 days.
    Similarly, Bs 1 days work = (1/10 -1/20) = 1/20.
    Therefore, B alone can finish the work in 20 days.
    And, Cs 1 days work= (1/10-1/12) = 1/60.
    Therefore, C alone can finish the work in 60 days.

Question: 27 -

If a clerk can process 80 cheques in half an hour, how many cheques can she process in a seven and one half hour day?

Options:

  1. 600

  2. 300

  3. 1200

  4. 800

    5. Answer:

    1200
    Solution:

    80 cheques in 1/2 hrs
    So in 7.5 hrs she can process,
    7.5*80/(1/2) = 1200

Question: 28 -

A task can be completed by D and E with in 12 days if they worked together. E and F however can complete with in period of 20 days. If three of them agree to work together then how many days will be required to complete the task ?

Options:

  1. 50

  2. 40

  3. 20

  4. none of these

    5. Answer:

    none of these
    Solution:

    D and E can complete within 12 days 
    and when F is also ready to work with D and E 
    obviously time required would be less than 12 days.

Question: 29 -

Hanuman can complete a bridge in 10 days and Ravanan can complete the same bridge in 20 days. Now they are working together and they are completing the bridge in 20 days. What is the contribution of Ravanan in constructing the bridge?

Options:

  1. (1/3)rd of the bridge

  2. (2/4)th of the bridge

  3. half the work

  4. Destructing the bridge

    5. Answer:

    Destructing the bridge
    Solution:

    Hanuman= 10 days so in 1 day= 1/10
    Ravanan = 20 days so in 1 day= 1/20
    If Ravanan helps Hanuman then their one day work will be =1/10+1/20= 3/20 so they can complete the bridge in 20/3 days= 6.33 days
    But acc. to the question the bridge is constructed in 20 days so its only possible when Ravanan is involved in 
    destructing the bridge coz (1/10-1/20)= 1/20 
    hence 20 days required to built the bridge.

Question: 30 -

A alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs 3200. With the help of C, they completed the work in 3 days. How much is to be paid to C?

Options:

  1. Rs. 600

  2. Rs. 400

  3. Rs. 375

  4. Rs.800

    5. Answer:

    Rs. 400
    Solution:

    A's 1 day work = 1/6
    B's 1 day work = 1/8
    So, C's 1 day's work = 1/3 - (1/6 + 1/8) = (1/3 - 7/24) = 1/24.
    So, A's wages : B's wages : C's wages
    => 1/6 : 1/8 : 1/24 = 4:3:1
    So, C's share = (1/8 * 3200) = Rs 400.