Time and Work


  1. 2 men and 1 woman together can complete a piece of work in 14 days, while 4 women and 2 men together can do it in 8 days. If a man gets ₹ 600 per day, how much should a woman get per day?









  1. View Hint View Answer Discuss in Forum

    According to the question,
    (2 × 14) men + 14 women = 16 men + 32 women
    ⇒ (28 – 16) men =(32–14) women
    ⇒ 12 men = 18 women
    ⇒ 2 men = 3 women

    ∴ 1 woman =
    2
    man
    3

    ∴ Amount received by 1 woman per day
    =
    2
    × 600 = ₹ 400
    3

    Correct Option: A

    According to the question,
    (2 × 14) men + 14 women = 16 men + 32 women
    ⇒ (28 – 16) men =(32–14) women
    ⇒ 12 men = 18 women
    ⇒ 2 men = 3 women

    ∴ 1 woman =
    2
    man
    3

    ∴ Amount received by 1 woman per day
    =
    2
    × 600 = ₹ 400
    3


  1. If 6 persons working 8 hours a day earn ₹ 8400 per week, then 9 persons working 6 hours a day will earn per week









  1. View Hint View Answer Discuss in Forum

    More persons,
    more earning
    Direct proportion x
    Less working hours,
    less earning

    6 : 9
    : : 8400 : x
    8 : 6

    ∴ 6 × 8 × x = 9 × 6 × 8400
    or x =
    9 × 6 × 8400
    = ₹ 9450
    6 × 8

    Aliter : Using Rule 1,
    Here, M1 = 6, T1 = 8, wages = x
    M2 = 9, T2 = 6, wages = 8400
    6 × 8 × x = 9 × 6 × 8400
    x =
    9 × 6 × 8400
    = Rs 9450
    6 × 8

    Correct Option: C

    More persons,
    more earning
    Direct proportion x
    Less working hours,
    less earning

    6 : 9
    : : 8400 : x
    8 : 6

    ∴ 6 × 8 × x = 9 × 6 × 8400
    or x =
    9 × 6 × 8400
    = ₹ 9450
    6 × 8

    Aliter : Using Rule 1,
    Here, M1 = 6, T1 = 8, wages = x
    M2 = 9, T2 = 6, wages = 8400
    6 × 8 × x = 9 × 6 × 8400
    x =
    9 × 6 × 8400
    = Rs 9450
    6 × 8



  1. 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 ₹ 3200. With the help of C they completed the work in 3 days. How much is to be paid to C ?









  1. View Hint View Answer Discuss in Forum

    Using Rule 25,

    A’s 1 day’s work =
    1
    6

    B’s 1 day’s work =
    1
    8

    (A + B + C)’s 1 day’s work =
    1
    3

    ∴ C’s 1day’s work
    1
    -
    1
    -
    1
    368

    =
    8 - 4 - 3
    =
    1
    2424

    ∴ Ratio of their one day’s work respectively
    1
    :
    1
    :
    1
    = 4 : 3 : 1
    6824

    Sum of the ratios = 4 + 3 + 1 = 8
    ∴ C’s share
    = ₹
    1
    × 3200 = ₹ 400
    8

    Correct Option: B

    Using Rule 25,

    A’s 1 day’s work =
    1
    6

    B’s 1 day’s work =
    1
    8

    (A + B + C)’s 1 day’s work =
    1
    3

    ∴ C’s 1day’s work
    1
    -
    1
    -
    1
    368

    =
    8 - 4 - 3
    =
    1
    2424

    ∴ Ratio of their one day’s work respectively
    1
    :
    1
    :
    1
    = 4 : 3 : 1
    6824

    Sum of the ratios = 4 + 3 + 1 = 8
    ∴ C’s share
    = ₹
    1
    × 3200 = ₹ 400
    8


  1. A and B can complete a piece of work in 15 days and 10 days respectively. They contracted to complete the work for ₹ 30,000. The share of A in the contracted money will be :









  1. View Hint View Answer Discuss in Forum

    A’s 1 day’s work =
    1
    15

    B’s 1 day’s work =
    1
    10

    Ratio =
    1
    :
    1
    = 2 : 3
    1510

    Sum of the ratios = 2 + 3 = 5
    ∴ A’s share
    = ₹
    2
    × 30000 = ₹ 12000
    5

    Aliter : Using Rule 24,
    Here, m = 15, n = 10, R = 30,000
    Share of A =
    n
    × R
    m + n

    =
    10
    × 30000
    15 + 10

    =
    10
    × 30000 = ₹ 12,000
    25

    Correct Option: D

    A’s 1 day’s work =
    1
    15

    B’s 1 day’s work =
    1
    10

    Ratio =
    1
    :
    1
    = 2 : 3
    1510

    Sum of the ratios = 2 + 3 = 5
    ∴ A’s share
    = ₹
    2
    × 30000 = ₹ 12000
    5

    Aliter : Using Rule 24,
    Here, m = 15, n = 10, R = 30,000
    Share of A =
    n
    × R
    m + n

    =
    10
    × 30000
    15 + 10

    =
    10
    × 30000 = ₹ 12,000
    25



  1. A man and a boy received ₹ 800 as wages for 5 days for the work they did together. The man’s efficiency in the work was three times that of the boy. What are the daily wages of the boy ?









  1. View Hint View Answer Discuss in Forum

    Man : boy = 3 : 1

    ∴ Boy's share =
    1
    × 800 = ₹ 200
    4

    ∴ The daily wages of boy
    = ₹
    200
    = ₹ 40
    5

    Aliter : Using Rule 16,
    A:B = 3x:x and A:B = t:3t
    Share of boy =
    t
    × 800 = 200
    t + 3t

    Daily wages of boy
    =
    200
    = ₹ 40
    5

    Correct Option: D

    Man : boy = 3 : 1

    ∴ Boy's share =
    1
    × 800 = ₹ 200
    4

    ∴ The daily wages of boy
    = ₹
    200
    = ₹ 40
    5

    Aliter : Using Rule 16,
    A:B = 3x:x and A:B = t:3t
    Share of boy =
    t
    × 800 = 200
    t + 3t

    Daily wages of boy
    =
    200
    = ₹ 40
    5