Ratio, Proportion


  1. Find the proportion in which three types of sugar at ₹ 12, ₹ 14 and ₹ 20 may be mixed so as to obtain a
    mixture worth 15 per kg ?









  1. View Hint View Answer Discuss in Forum


    Required proportion = 5 : 5 : (3 + 1 ) o r 5 : 5 : 4 .
    Note : We can find other alternatives too by adding multiples of the quantities obtained at I and II. This will give us infinite number of alternatives. Care must be taken not to mix up quantities of one pair with another
    For example ,

    Correct Option: B


    Required proportion = 5 : 5 : (3 + 1 ) o r 5 : 5 : 4 .
    Note : We can find other alternatives too by adding multiples of the quantities obtained at I and II. This will give us infinite number of alternatives. Care must be taken not to mix up quantities of one pair with another
    For example ,


  1. In what proportion may three kinds of rice bought at ₹ 6 , ₹ 10 and ₹ 14 be mixed to produce a mixture
    which would earn 40% on selling it at ₹ 11.20 per kg ?









  1. View Hint View Answer Discuss in Forum

    SP o f mixture
    = ₹ 11.20 per kg .
    Profit = 40% .

    CP of mixture ; 11.20 "
    100
    140

    = ₹ 8 per kg .

    R e q u ire d ra tio
    = 8 : 2 : 2 or 4 :1 : 1 .

    Correct Option: A

    SP o f mixture
    = ₹ 11.20 per kg .
    Profit = 40% .

    CP of mixture ; 11.20 "
    100
    140

    = ₹ 8 per kg .

    R e q u ire d ra tio
    = 8 : 2 : 2 or 4 :1 : 1 .



  1. In what proportion may three kinds of tea prices at ₹ 80, ₹ 70 and ₹ 50 per kg be mixed to produce a mixture worth ₹ 60 per kg?









  1. View Hint View Answer Discuss in Forum

    Write the prices in ascending or descending order as shown below :

    Make pairs by choosing one from each side of the mean price and apply A llig a tio n Rule . The n a d d
    the quantity obtained under each price . This will give the ratio in which the ingredients should be mixed .

    So , Required ratio
    = 10 : 10 : 30 or 1 :1 : 3 .

    Correct Option: D

    Write the prices in ascending or descending order as shown below :

    Make pairs by choosing one from each side of the mean price and apply A llig a tio n Rule . The n a d d
    the quantity obtained under each price . This will give the ratio in which the ingredients should be mixed .

    So , Required ratio
    = 10 : 10 : 30 or 1 :1 : 3 .


  1. In what ratio a trader should mix two varieties of tea one at ₹ 62 per kg and other at ₹ 72 per kg in order to obtain the mixture worth ₹ 65 per kg ?









  1. View Hint View Answer Discuss in Forum

    C.P. of 1 kg tea of Ist quality = ₹ 62
    C.P. of 1 kg tea of 2nd quality= ₹ 72.
    Mean Price = ₹ 65

    Using Alligation Rule ,

    Quantity of 1st tea
    ;
    d − m
    ;
    7
    Quantity of 2nd team − c3

    Therefore , they must be mixed in the ratio of 7 : 3 .
    [Since this problem is the inverse of above type problem , it is called ‘Alligation alternate ’].

    Correct Option: B

    C.P. of 1 kg tea of Ist quality = ₹ 62
    C.P. of 1 kg tea of 2nd quality= ₹ 72.
    Mean Price = ₹ 65

    Using Alligation Rule ,

    Quantity of 1st tea
    ;
    d − m
    ;
    7
    Quantity of 2nd team − c3

    Therefore , they must be mixed in the ratio of 7 : 3 .
    [Since this problem is the inverse of above type problem , it is called ‘Alligation alternate ’].



  1. A shopkeeper mixes 12 kgs of rice at ₹ 8 per kg with 6 kgs of rice at 10 per kg . Find the cost per kg of the mixture .









  1. View Hint View Answer Discuss in Forum

    Total quantity of the mixture
    = 12 + 6 = 18 kgs .
    Cost of 12 kgs of rice at ₹ 8 per kg = ₹ (12 × 8) = ₹ 96
    Cost of 6 kgs of rice at ₹ 10 per kg
    = ₹ (6 × 10) = ₹ 60
    ∴  Total cost of 18 kgs of the mixture
    = ₹ (96 + 60) = ₹ 156
    ∴  Cost per kg of the mixture

    =
    Rs. 156
    ; ₹ 8.67 per kg
    18 kgs

    [Because cost of the mixture lies somewhere in the middle of ₹ 8 and ₹ 10, so this type of problem is known as ‘Alligation medial’].

    Correct Option: A

    Total quantity of the mixture
    = 12 + 6 = 18 kgs .
    Cost of 12 kgs of rice at ₹ 8 per kg = ₹ (12 × 8) = ₹ 96
    Cost of 6 kgs of rice at ₹ 10 per kg
    = ₹ (6 × 10) = ₹ 60
    ∴  Total cost of 18 kgs of the mixture
    = ₹ (96 + 60) = ₹ 156
    ∴  Cost per kg of the mixture

    =
    Rs. 156
    ; ₹ 8.67 per kg
    18 kgs

    [Because cost of the mixture lies somewhere in the middle of ₹ 8 and ₹ 10, so this type of problem is known as ‘Alligation medial’].