Time and Work


  1. The rates of working of A and B are in the ratio 3 : 4. The number of days taken by them to finish the work are in the ratio ?









  1. View Hint View Answer Discuss in Forum

    Radio of times taken = (1/3) : (1/4)

    Correct Option: C

    Radio of times taken = (1/3) : (1/4) = 4 : 3


  1. A does half as much work as B in three-fourth of the time. If the together they take 18 days to complete a work. How much time shall B take to do it ?









  1. View Hint View Answer Discuss in Forum

    Let B takes x days to do the work
    ∴ A takes (2 x 3 / 4 x) = 3 x / 2 days to do it
    ∵ (A + B)'s 1 day's work = 1 / 18

    Correct Option: C

    Let B takes N days to do the work
    ∴ A takes 2 x (3/4) x N = 3N/2 days to do it
    ∵ (A + B)'s 1 day's work = 1/18
    ⇒ 1/N + 2/3N = 1/18
    ∴ N = 30



  1. A and B together can do a work in 24 days. B alone does its 1/3 part in 12 days. How long will A alone take to do the remaining work ?









  1. View Hint View Answer Discuss in Forum

    Work done by (A + B) in 1 day = 1/24
    Work done by B alone in 1 day = 1/(3 x 12) = 1/36
    ∴ Work of A for 1 day = 1/24 - 1/36 = 1/72
    After 12 days the remaining work = 1 - 1/3 = 2/3

    Correct Option: A

    Work done by (A + B) in 1 day = 1/24
    Work done by B alone in 1 day = 1/(3 x 12) = 1/36
    ∴ Work of A for 1 day = 1/24 - 1/36 = 1/72
    After 12 days the remaining work = 1 - 1/3 = 2/3
    ∵ 1/72 work is done by A in 1 day
    ∴ 2/3 work is done by A in (1 x 72)/(1 x 2/3) = 48 days


  1. 15 men complete a work in 16 days If 24 men are employed then the time require to complete that work will be









  1. View Hint View Answer Discuss in Forum

    let the work done be 1 work.
    Here M1=15, D1=16 W1=W2 =1
    M2 =24 D2= ?
    ∴ According to the formula
    M1 D1 W2 = M2 D2 W1

    Correct Option: C

    let the work done be 1 work.
    Here M1=15, D1=16 W1=W2 =1
    M2 =24 D2= ?
    ∴ According to the formula
    M1 D1 W2 = M2 D2 W1
    ⇒ 15 x 16 x 1 = 24 x D2 X 1
    ∴ D1 = 15 X 16/24 = 10
    Therefore 10 days are required to complete the work



  1. A can complete a piece of work in 18 days and B can complete the same work in half time taken by A. Then, working together, what part of the same work they can complete in a day?











  1. View Hint View Answer Discuss in Forum

    A's 1 day's work = 1/18
    B's 1 day's work = 1/9

    Correct Option: A

    A's 1 day's work = 1/18
    B's 1 day's work = 1/9
    (A + B)'s 1 day's work = 1/9 + 1/18 = 3/18 = 1/6