Ratio, Proportion


  1. A mixture contains milk and water in the ratio 5 : 1. On adding 5 litres of water, the ratio of milk and water becomes 5 : 2. The quantity of milk in the mixture is :









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    Quantity of milk in the mixture = 5x litres
    Quantity of water = x litres
    According to the question,
    On adding 5 litres of water,

    5x
    =
    5
    x + 52

    ⇒  10x = 5x + 25
    ⇒  5x = 25 ⇒ x = 5
    ∴  Required quantity of milk
    = 5 × 5 = 25 litres

    Correct Option: A

    Quantity of milk in the mixture = 5x litres
    Quantity of water = x litres
    According to the question,
    On adding 5 litres of water,

    5x
    =
    5
    x + 52

    ⇒  10x = 5x + 25
    ⇒  5x = 25 ⇒ x = 5
    ∴  Required quantity of milk
    = 5 × 5 = 25 litres


  1. 20 litres of a mixture contains milk and water in the ratio 3 : 1. Then the amount of milk to be added to the mixture so as to have milk and water in ratio 4 : 1 is :









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    In 20 litres of mixture,

    Milk ⇒
    3
    × 20 = 15 litres
    4

    Water ⇒
    1
    × 20 = 5 litres
    4

    Let the quantity of milk added be x litres.
    According to the question,
    15 + x
    =
    4
    51

    ⇒  15 + x = 4 × 5
    ⇒  x = 20 – 15 = 5 litres

    Correct Option: C

    In 20 litres of mixture,

    Milk ⇒
    3
    × 20 = 15 litres
    4

    Water ⇒
    1
    × 20 = 5 litres
    4

    Let the quantity of milk added be x litres.
    According to the question,
    15 + x
    =
    4
    51

    ⇒  15 + x = 4 × 5
    ⇒  x = 20 – 15 = 5 litres



  1. Two blends of a commodity costing Rs. 35 and Rs. 40 per kg. respectively are mixed in the ratio 2 : 3 by weight. If one–fifth of the mixture is sold at Rs. 46 per kg and the remaining at the
    rate of Rs. 55 per kg. the profit percent is









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    Let 5 kg of mixture be prepared.
    ∴  C.P. of 5 kg of mixture
    = Rs. (2 × 35 + 3 × 40)
    = Rs. (70 + 120)
    = Rs. 190
    Total S.P. of this mixture
    = Rs. (46 + 4 × 55)
    = Rs. (46 + 220) = Rs. 266
    ∴  Profit per cent

    =
    266 − 190
    × 100
    190

    =
    7600
    = 40%
    190

    Correct Option: C

    Let 5 kg of mixture be prepared.
    ∴  C.P. of 5 kg of mixture
    = Rs. (2 × 35 + 3 × 40)
    = Rs. (70 + 120)
    = Rs. 190
    Total S.P. of this mixture
    = Rs. (46 + 4 × 55)
    = Rs. (46 + 220) = Rs. 266
    ∴  Profit per cent

    =
    266 − 190
    × 100
    190

    =
    7600
    = 40%
    190


  1. Three glasses of equal volume contains acid mixed with water. The ratios of acid and water are 2 : 3, 3 : 4 and 4 : 5 respectively. Contents of these glasses are poured in a large vessel. The ratio of acid and water in the large vessel is









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    Let the capacity of each glass be 1 litre.
    On mixing all three mixtures together,

    Acid ⇒
    2
    +
    3
    +
    4
    579

    =
    126 + 135 + 140
    315

    =
    401
    litre
    315

    Water ⇒
    3
    +
    4
    +
    5
    579

    =
    189 + 180 + 175
    =
    544
    315315

    ∴  Required ratio =
    401
    :
    544
    315315

    Correct Option: B

    Let the capacity of each glass be 1 litre.
    On mixing all three mixtures together,

    Acid ⇒
    2
    +
    3
    +
    4
    579

    =
    126 + 135 + 140
    315

    =
    401
    litre
    315

    Water ⇒
    3
    +
    4
    +
    5
    579

    =
    189 + 180 + 175
    =
    544
    315315

    ∴  Required ratio =
    401
    :
    544
    315315



  1. 60 kg of an alloy A is mixed with 100 kg of alloy B. If alloy A has lead and tin in the ratio 3 : 2 and alloy B has tin and copper in the ratio 1 : 4, the amount of tin in the new alloy is









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    In 60 kg of alloy A,

    Lead =
    3
    × 60 = 36 kg.
    5

    Tin =
    2
    × 60 = 24 kg.
    5

    In 100 kg of alloy B,
    Tin =
    1
    × 100 = 20 kg.
    5

    In 160 kg of new alloy,
    Tin = 24 + 20 = 44 kg.

    Correct Option: B

    In 60 kg of alloy A,

    Lead =
    3
    × 60 = 36 kg.
    5

    Tin =
    2
    × 60 = 24 kg.
    5

    In 100 kg of alloy B,
    Tin =
    1
    × 100 = 20 kg.
    5

    In 160 kg of new alloy,
    Tin = 24 + 20 = 44 kg.