16Jun, 2021
Quantitative Aptitude: Time and Work Set 25
  1. A can do a piece of work in 25 days. If B is 20% more efficient than A, then in how many days three – fifth of the work is completed by A and B working together ?
    2 3/4 days
    8 1/5 days
    4 days
    6 9/11 days
    6 11/14 days
    Option D
    Let efficiency A = 5
    efficiency of B = 5 *6 /5 = 6
    total work = 25 * 5 = 125
    3/5 of the work = 3/5*125 = 75
    time = 75/5+6 = 6 9/11days

     

  2. A can do 1/5 of the work in 5 days and B can do 1/4 of the work in 6 days. If they earned total rs.4900, then how much money will A get ?
    2400
    4800
    2500
    3200
    1450
    Option A
    A can do total work = 5 * 5 = 25 days
    B can do total work = 4 * 6 = 24 days
    LCM of 25 and 24 = 600
    Total work = 600
    efficiency of A = 600/25 = 24
    efficiency of B = 600/24 = 25
    A get = 4900 * 24/49 = 2400

     

  3. P, Q and R can do a piece of work in 20 days, 30 days and 40 days respectively. If they started the work together but after 6 days P left the work and remaining work done by Q and R together, they in how many days total work will be completed ?
    14 days
    12 days
    20 days
    16 days
    6 days
    Option B
    LCM of 20, 30 and 40 = 120
    total work = 120
    efficiency of P = 120/20 = 6
    efficiency of Q = 120/30 = 4
    efficiency of R = 120/40 = 3
    they completed the work together in 6 days = (6 + 4 + 3)6 = 78
    remaining work = 120 – 78 = 42
    time taken by Q and R together to complete remaining work = 42/4+3 = 6 days
    total time = 6 + 6 = 12 days

     

  4. A group of 25 men is supposed to do a work in 30 days. After 15 days 5 more men is employed and the work is employed in 1 day before the scheduled time. If 5 more men were not employed, then in how many days it have been delayed ?
    2
    3.2
    1.9
    2.5
    1.8
    Option E
    work completed by 25 men in 15 days = 25 * 15 = 375
    now total men = 25 + 5 = 30
    work completed before 1 day
    total work = 375 + 30 * 14 = 795
    If 5 men is not employed,
    time taken by 25 men to complete work = 795/25 = 31.8
    work will be delayed = 31.8 – 30 = 1.8 day

     

  5. A and B can do a piece of work in 18 days and 24 days respectively. If they work in alternative day starting with A, then in how many days the work is completed ?
    22 2/5
    20 4/8
    20 1/2
    3/4
    3
    Option C
    LCM of 18 and 24 = 72
    Total work = 72
    efficiency of A = 72/18 = 4
    efficiency of B = 72/24 = 3
    A and B work in alternate day.
    A and B completed work in 2 days = 4 + 3 = 7
    10(2 day) = 10(7 work)
    20 day = 70 work
    A completed 4 work in 1 day so, 2 work completed in 1/2 day.
    total time = 20 + 1/2 = 20 1/2 day.

     

  6. A and B can do a piece of work in 25 days and 30 days respectively and they start working together for 10 days. After 10 days A left the work and C joins and the remaining work in completed by B and C together in 5 days. Find the days in which C can do the work ?
    50 days
    40 days
    46 days
    32 days
    58 days
    Option A
    LCM of 25 and 30 = 150
    total work = 150
    efficiency A = 150/25 = 6
    efficiency of B = 150/30 = 5
    A and B completed work in 10 days = (6 + 5) 10 = 110
    remaining of work = 150 – 110 = 40
    B and C completed in 5 days = 40/5 = 8
    efficiency of C = 8 – 5 = 3
    C alone completed total work = 150/3 = 50 days.

     

  7. A and B can do a piece of work in 20 days and 30 days respectively. They start working together after some days A left the work and remaining work completed by B in 15 days. Find in how many days A left the work ?
    20
    6
    4
    12
    8
    Option B
    LCM of 20 and 30 = 60
    efficiency of A = 60/20 = 3
    efficiency of B = 60/30 = 2
    B alone work for 15 days = 15 * 2 = 30 work
    Time taken to do remaining by A and B together = 30/3+2 = 6 days
    After 6 days A left the work.

     

  8. A can do 80% of a work in 20 days. A and B together can do the remaining work in 4 days. Then in how many days B alone would take to do the total work ?
    120
    130
    50
    40
    100
    Option E
    A work done = 20*5/4 = 25 days
    Remaining work = 1/5
    time taken by A and B to do total work = 5 * 4 = 20 days
    LCM of 25 and 20 = 100
    efficiency of A = 100/25 = 4
    efficiency of A and B = 100/20 = 5
    efficiency of B = 5 – 4 = 1
    Time taken by B to do total work = 100/1 = 100 days

     

  9. P and Q can do a piece of work in 20 days and 40 days respectively. They start the work but Q leaves the work 8 days before the completion. Find how many days is required to complete the work ?
    4
    8
    12
    14
    20
    Option B
    LCM of 20 days and 40 days = 40
    Total work = 40
    efficiency of P = 40/20 = 2
    efficiency of Q = 40/40 = 1
    work done by P in 8 days = 8 * 2 = 16 days
    Remaining work = 40 – 16 = 24 work
    Time taken by P and Q remaining work = 24/2+1 = 8 days

     

  10. A and B undertake to complete a work for rs.3000. A and B can do a piece of work on 12 days and 15 days respectively and with the help of C they complete the work in 4 days. Then how much money C get ?
    1200
    1320
    1840
    1540
    1450
    Option A
    LCM of 12, 15 = 60
    Total work = 60
    efficiency of A = 60/12 = 5
    efficiency of B = 60/15 = 4
    total efficiency of A, B and C = 60/4 = 15
    efficiency of C = 15 -(5 + 4) = 6
    share of C = 3000 * 6/15 = 1200