Quantitative Aptitude: Time and Work Set 27

  1. A, B and C alone can do a work in 8 days , 12 days and 6 days respectively. Find how many days they take together to complete work ?
    6 days
    8 days
    2 2/3 days
    4 days
    3 days
    Option C
    LCM of 8 , 12 and 6 = 24
    total work = 24
    efficiency of A = 24/8 = 3
    efficiency of B = 24/12 = 2
    efficiency of C = 24/6 = 4
    time taken = 24/9 = 2 2/3 days

     

  2. P and Q alone can do a work in 30 days and 20 days respectively. P works for 15 days and left the work, remaining work done by B. Find how many days required to complete the remaining work ?
    10 days
    8 days
    20 days
    18 days
    16 days
    Option A
    LCM of 30 and 20 = 60
    total work = 60
    efficiency of P = 60/30 = 2
    efficiency of Q = 60/20 = 3
    P completed work in 15 days = 15 * 2 = 30
    time taken by Q to complete remaining work = 60 – 30 /3 = 10 days

     

  3. A can complete 40% of work in 8 hours and while B alone can do the same work in 24 hours. Find the time taken by A and B together to complete the 60% of the work ?
    5 2/3 days
    8 3/5 days
    4 days
    6 6/11 days
    8 days
    Option D
    A alone can do all work = 8/40 * 100 = 20 days
    LCM of 20 and 24 = 120
    efficiency of A = 120/20 = 6
    efficiency of B = 120/24 = 5
    time taken by A and B together to complete 60% of the work = 120/11 * 60/100 = 6 6/11 days

     

  4. A and B alone can do a piece of work in 12 hours and 15 hours respectively. If they do the work alternatively for 1 hours each starting with A, then find how many hours will the work be completed ?
    5 hours
    3 hours
    8 1/5 hours
    12 1/4 hours
    13 1/4 hours
    Option E
    LCM of 12 and 15 = 60
    total work = 60
    efficiency of A = 60/12 = 5
    efficiency of B = 60/15 = 4
    work completed in 2 hours = 5 + 4 = 9 works
    (2 * 6) hours = (9 * 6) work
    12 hours = 54 works
    A works in another hours = 5 work
    remaining 1 work completed by B = 14 hours
    total time = 12 + 1 + 1/4 = 13 1/4 hours

     

  5. A, B and C alone can do a piece of work in 3 days. If A alone can do in 6 days and C alone can do it in 18 days, how long will B alone take to complete the work ?
    8 days
    9 days
    18 days
    6 days
    4 days
    Option B
    LCM of 3, 6 and 18 = 18
    total work = 18
    efficiency of A, B and C = 18/3 = 6
    efficiency of A = 18/6 = 3
    efficiency of C = 18/18 = 1
    efficiency of B = 6 – ( 3 + 1 ) = 2
    B alone can do the work = 18/2 = 9 days

     

  6. P and Q undertook to do a piece of work for rs.3500. P alone can do it in 12 days and Q alone in 20 days. If they finished the work with the help of R in 6 days. What is share of R ?
    800
    700
    850
    650
    725
    Option B
    LCM of 12, 20 and 6 = 60
    efficiency of P = 60/12 = 5
    efficiency of Q = 60/20 = 3
    efficiency of P, Q and R = 60/6 = 10
    efficiency of R = 10 – ( 5 + 3 ) = 2
    share of R = 3500 * 2 / 10 = 700

     

  7. Rita and Gita can do a piece of work individually in 40 days and 60 days respectively. If they work on alternate days starting with Gita, then in how many days will the work get finished ?
    28 days
    24 days
    17 days
    48 days
    46 days
    Option D
    LCM of 40 and 60 = 120
    efficiency of Rita = 120/40 = 3
    efficiency of Gita = 120/60 = 2
    starting with Gita work completed in 2 days = 5
    time required to complete total work = 24 * 2 = 48 days

     

  8. A and B can do a work in 12 days. B and C can do the same work in 20 days. A and C can also do the same work in 30 days. If they all work together in how many days will they complete the work ?
    10 days
    14 days
    12 days
    13 days
    15 days
    Option C
    LCM of 12, 20 and 30 = 120
    efficiency of A and B = 120/12 = 10
    efficiency of B and C = 120/20 = 6
    efficiency of A and C = 120/30 = 4
    A + B + B + C + A + C = 10 + 6 + 4 = 20
    2(A + B + C) = 20
    A + B + C = 10
    time 120/10 = 12 days

     

  9. 8 men or 12 women can finish a work in 25 days. How many days will 6 men ad 11 women can finish the same work ?
    15 days
    14 days
    28 days
    30 days
    32 days
    Option A
    8 men = 12 women
    men/women = 12/8 = 3/2
    total work = 8 * 3 * 25 = 600
    time required = 600 /(6 * 3 + 11 * 2) = 600/40 = 15 days

     

  10. A, B and C can complete a job in 9 days, 10 days and 15 days respectively. A, B and C start the work together and after 2 days B and C leave the work. Find how many days taken by A to complete the remaining work ?
    6 days
    18 days
    14 days
    4 days
    8 days
    Option D
    LCM of 9, 10 and 15 = 90
    efficiency of A = 90/9 = 10
    efficiency of B = 90/10 = 9
    efficiency of C = 90/15 = 6
    A, B and C complete work in 2 days = 2(10 + 9 + 6) = 50
    remaining work = 90 – 50 = 40
    time taken by A to complete remaining work = 40/10 = 4 days

     

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