Ratio, Proportion


  1. 200 litres of a mixture contains milk and water in the ratio 17 : 3. After the addition of some more milk to it, the ratio of milk to water in the resulting mixture becomes 7 : 1. The quantity of milk added to it was









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    Let the quantity of additional milk added = x litres
    In the mixture of 200 litres,

    Quantity of milk =
    17
    × 200
    20

    = 170 litres
    Quantity of water = 30 litres
    According to the question,
    170 + x
    =
    7
    301

    ⇒  170 + x = 210
    ⇒  x = 210 – 170
    = 40 litres

    Correct Option: B

    Let the quantity of additional milk added = x litres
    In the mixture of 200 litres,

    Quantity of milk =
    17
    × 200
    20

    = 170 litres
    Quantity of water = 30 litres
    According to the question,
    170 + x
    =
    7
    301

    ⇒  170 + x = 210
    ⇒  x = 210 – 170
    = 40 litres


  1. A can contains a mixture of two liquids A and B in the ratio 7 : 5. When 9 litres of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7 : 9. Litres of liquid A
    contained by the can initially was









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    Let A = 7x litre, B = 5x litre
    In 9 litres of mixture,

    A =
    7x
    × 9 =
    21
    litres
    12x4

    B =
    5x
    × 9 =
    15
    litres
    12x4

    In new situation,
    7x −
    21
    = 7/9
    4
    5x −
    15
    + 9
    4

    ⇒ 
    28x − 21
    =
    7
    20x − 15 + 369

    ⇒  252x – 189 = 140x + 147
    ⇒  112x = 336 ⇒ x = 3
    ∴  Initial quantity of liquid A
    = 7x = 7 × 3 = 21 litres

    Correct Option: C

    Let A = 7x litre, B = 5x litre
    In 9 litres of mixture,

    A =
    7x
    × 9 =
    21
    litres
    12x4

    B =
    5x
    × 9 =
    15
    litres
    12x4

    In new situation,
    7x −
    21
    = 7/9
    4
    5x −
    15
    + 9
    4

    ⇒ 
    28x − 21
    =
    7
    20x − 15 + 369

    ⇒  252x – 189 = 140x + 147
    ⇒  112x = 336 ⇒ x = 3
    ∴  Initial quantity of liquid A
    = 7x = 7 × 3 = 21 litres



  1. A container contains two liquids A and B in the ratio 7 : 5. When 9 litres of mixture are drawn off and the container is filled with B, the ratio of A and B becomes 1:1. How many litres of liquid A was in the container initially ?









  1. View Hint View Answer Discuss in Forum

    Let Liquid A = 7x litres
    Liquid B = 5x litres
    In 9 litres,

    A =
    7
    × 9 =
    21
    litres
    124

    B =
    5
    × 9 =
    15
    litres
    124

    ∴  7x −
    21
    = 5x −
    15
    + 9
    44

    ⇒  2x =
    21
    15
    + 9
    44

    ⇒  2x =
    21 − 15 + 36
    =
    42
    44

    ⇒  x =
    21
    4

    ∴  Liquid A = 7 ×
    21
    4

    =
    147
    = 36
    3
    litre
    44

    Correct Option: C

    Let Liquid A = 7x litres
    Liquid B = 5x litres
    In 9 litres,

    A =
    7
    × 9 =
    21
    litres
    124

    B =
    5
    × 9 =
    15
    litres
    124

    ∴  7x −
    21
    = 5x −
    15
    + 9
    44

    ⇒  2x =
    21
    15
    + 9
    44

    ⇒  2x =
    21 − 15 + 36
    =
    42
    44

    ⇒  x =
    21
    4

    ∴  Liquid A = 7 ×
    21
    4

    =
    147
    = 36
    3
    litre
    44


  1. A and B are two alloys of gold and copper prepared by mixing metals in ratios 7 : 2 and 7 : 11 respectively. If equal quantities of the alloys are melted to form a third alloy C, the ratio of gold and copper in C will be ;









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    Gold =
    7
    :
    7
    =
    14
    :
    7
    9181818

    ∴  Gold in new mixture
    = 14 + 7 = 21
    and copper = 18 × 2 – 21
    = 36 – 21 = 15
    ∴  Required ratio
    = 21 : 15 = 7 : 5

    Correct Option: A

    Gold =
    7
    :
    7
    =
    14
    :
    7
    9181818

    ∴  Gold in new mixture
    = 14 + 7 = 21
    and copper = 18 × 2 – 21
    = 36 – 21 = 15
    ∴  Required ratio
    = 21 : 15 = 7 : 5



  1. The ratio in which a man must mix rice at 10.20 per kg and 14.40 per kg so as to make a
    mixture worth 12.60 per kg, is









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    ∴  Required ratio = 1.8 : 2.4
    = 18 : 24 = 3 : 4

    Correct Option: D


    ∴  Required ratio = 1.8 : 2.4
    = 18 : 24 = 3 : 4