Time and Work


  1. X can completed a job in 12 days. If X and Y work together, they can complete the job in 62/3 days, Y alone can complete the job in









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    X's 1 day's work = 1/12
    (X + Y)' s 1 day's work = 3/20
    ∴ Y's 1 day's work = (3/20) - (1/12) = 4/60 = 1/15

    Correct Option: C

    X's 1 day's work = 1/12
    (X + Y)' s 1 day's work = 3/20
    ∴ Y's 1 day's work = (3/20) - (1/12) = 4/60 = 1/15
    ∴ Number of day's taken by Y to complete the work = 15 days


  1. 10 men can make a wall in 8 days. How many men required to complete the same work in half days ?









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    Given M1 = 10
    D1 = 8, M2= ? and D2 = 1/2
    From M1 D1 = M2 D2

    Correct Option: D

    Given M1 = 10
    D1 = 8, M2= ? and D2 = 1/2
    From M1 D1 = M2 D2
    ⇒ 10 x 8 = M2 x 1/2
    ⇒ M2= 10 x 8 x 2
    ∴ M2 = 160



  1. 3 men can do a piece of work in 6 days. 5 women can do the same work in 18 days. If 4 men and 10 women work together, then how long will it take to finish the work ?











  1. View Hint View Answer Discuss in Forum

    (3 x 6) men = (5 x 18) women
    18 men = 90 women
    ∴ 1 man = 5 women
    ∴ 4 men + 10 women
    = 4 x 5 + 10 = 30 women
    Given, M1 = 5, M2 = 20, D1 = 18 ,
    W1 = W2 = 1 and D2 = ?
    According to the formula, M1D1W2 = M2D2W1

    Correct Option: A

    (3 x 6) men = (5 x 18) women
    18 men = 90 women
    ∴ 1 man = 5 women
    ∴ 4 men + 10 women
    = 4 x 5 + 10 = 30 women
    Given, M1 = 5, M2 = 20, D1 = 18 ,
    W1 = W2 = 1 and D2 = ?
    According to the formula, M1D1W2 = M2D2W1
    ⇒ 5 x 18 x 1 = 30 x D2 x 1
    ∴ D2 = 5 x 18/30 = 3 days


  1. 3 men can do a piece of work in 18 days. 6 children can also do that work in 18 days. 4 men and 4 children together will finish the work in how many days ?











  1. View Hint View Answer Discuss in Forum

    3 men = 6 children
    ⇒ 1 man = 2 children
    ∴ 4 men + 4 children = 4 men + (4/2) men = 6 men
    Given, M1 = 3, M2 = 6, D1 = 18, W1 = W2 = 1 and D2= ?
    According to the formula,
    M1D1W2 = M2D2W1

    Correct Option: D

    3 men = 6 children
    ⇒ 1 man = 2 children
    ∴ 4 men + 4 children = 4 men + (4/2) men = 6 men
    Given, M1 = 3, M2 = 6, D1 = 18, W1 = W2 = 1 and D2= ?
    According to the formula,
    M1D1W2 = M2D2W1
    ⇒ 3 x 18 x 1 = 6 x D2 x 1
    ∴ D2 = 3 x 18/6 = 9 days



  1. P can do piece of work in 12 days, while Q alone can finish it in 8 days. With the help of R, they can finish the work in 4 days. How long will R take to finish the work alone ?











  1. View Hint View Answer Discuss in Forum

    P,s 1 day's work = 1/12
    Q's 1 day's work = 1/8
    (P + Q)'s 1 day's work = (1/12) + (1/8)
    = (2 + 3)/24
    = 5/24

    (P + Q + R)'s 1 day's work = 1/4
    ∴ R's 1 day's work = (1/4) - (5/24) = (6 - 5)/24 = 1/24

    Correct Option: D

    P,s 1 day's work = 1/12
    Q's 1 day's work = 1/8
    (P + Q)'s 1 day's work = (1/12) + (1/8)
    = (2 + 3)/24
    = 5/24

    (P + Q + R)'s 1 day's work = 1/4
    ∴ R's 1 day's work = (1/4) - (5/24) = (6 - 5)/24 = 1/24
    ∴ R will finish the work alone in 24 days.
    ∴ Required time = 24 days