Alligation or Mixture


  1. In what ratio must water be added to spirit to gain 25% by selling it at cost price?









  1. View Hint View Answer Discuss in Forum

    Let cost price of spirit be Re. 1 per liter.
    Then SP of mixture = Re. 1 per liter
    Gain = 25%


    Correct Option: A

    Let cost price of spirit be Re. 1 per liter.
    Then SP of mixture = Re. 1 per liter
    Gain = 25%
    So, CP of mixture = 1 × (100 / 125) = Re. 4 / 5
    We assume that CP of water is zero.
    Using allegation rule on cost price,
    Water should be mixed to spirit in the ratio (1 / 5) : (4 / 5) or 1 : 4



  1. 6 liters of milk and water mixture has 75% milk in it. How much milk should be added to the mixture to make it 90% pure?









  1. View Hint View Answer Discuss in Forum

    The given solution has 75% milk.
    Milk to be added has 100% milk.


    Correct Option: B

    The given solution has 75% milk.
    Milk to be added has 100% milk.
    Milk should be added to the given mixture in the ratio 15 : 10 or 3 : 2
    ∴ Quantity of milk to be added = (3 / 2) × 6 = 9 liters.




  1. Two vessels A and B contain mixture of milk and water in the ratio 4 : 1 and 9 : 11 respectively. They are mixed in the ratio of 3 : 2. Find the ratio of milk and water in the resulting mixture.









  1. View Hint View Answer Discuss in Forum

    Fraction is Milk Water
    A: 4 / 5 1 / 5
    B: 9 / 20 11 / 20
    (3A + 2B) = A and B: ((12 / 5) + (9 / 10)) ((3 / 5) + (11 / 10))

    Correct Option: B

    Fraction is Milk Water
    A: 4 / 5 1 / 5
    B: 9 / 20 11 / 20
    (3A + 2B) = A and B: ((12 / 5) + (9 / 10)) ((3 / 5) + (11 / 10))

    (33 / 10) (17 / 10)
    So, Ratio of milk: water in the resulting mixture = 33: 17.


  1. A shopkeeper buys 26 liter of milk @ Rs. 16 per liter. He also buys from another source an inferior quality of milk @ Rs. 10 per liter. How much quantity of the later should he buy to mix it with the former so that he can sell the mixture @ Rs. 14 per liter without making any loss?









  1. View Hint View Answer Discuss in Forum

    Quantity of milk @ Rs.10 per liter/ Quantity of milk @ Rs. 16 per liter= 1 / 2



    Correct Option: A

    Quantity of milk @ Rs.10 per liter / Quantity of milk @ Rs. 16 per liter = 1 / 2
    So, quantity of milk @ Rs. 10 per liter = 26 / 2 = 13 liter.

    2nd Method
    Let us assume shopkeeper buy P liter milk of price @ Rs. 10 per liter.
    Buy price of 26 liter of milk @ Rs. 16 per liter = 26 x 16
    Buy price of P liter of milk @ Rs. 10 per liter = P x 10
    Sell price of total milk ( P + 26 ) @ Rs. 14 per liter = 14 x ( P + 26 )
    According to question there is no loss or no profit.
    Then Buy Price = Sell Price
    26 x 16 + P x 10 = 14 x ( P + 26 )
    ⇒ 26 x 16 + 10P = 14P + 14 x 26
    ⇒ 26 x 16 - 26 x 14 = 14P - 10P
    ⇒ 2 x 26 = 4P
    ⇒ 4P = 2 x 26
    ⇒ P = 2 x 26 / 4 = 13

    So, quantity of milk @ Rs. 10 per liter = 13 liter.




  1. 640 ml of a mixture contains milk and water in ratio 6:2. How much of the water is to be added to get a new mixture containing half milk and half water ?











  1. View Hint View Answer Discuss in Forum

    Let us assume the ratio factor is Q.
    According to question,
    Quantity of Milk in mixture = 6Q ml
    Quantity of Water in mixture = 2Q ml
    Quantity of Milk in mixture + Quantity of Water in mixture = 640
    Proceed and solve the equation as per given question.

    Correct Option: B

    Let us assume the ratio product is Q.
    According to question,
    Quantity of Milk in mixture = 6Q ml
    Quantity of Water in mixture = 2Q ml
    Quantity of Milk in mixture + Quantity of Water in mixture = 640
    6Q + 2Q = 640
    8Q = 640
    Q = 640/8
    Q = 80
    Quantity of Milk in mixture = 6Q ml = 6 x 80 = 480 ml
    Quantity of Water in mixture = 2Q ml = 2 x 80 = 160 ml
    To find the new mixture containing half milk and half water,
    Quantity of water to be added for making the mixture of equal quantity of milk and water = 480 - 160 = 320