A recipe calls for 1 cup of milk for every cups of flour to make a cake that would feed 6 persons. How many cups of both flour and milk will be needed to make a similar cake for 8 people?



The ratio of number of cups of milk to number of people is constant


When number of cups of milk = 1 number of people are 6


ratio = = …(i)


When number of people are 8 let number of cups of milk required be ‘a’


ratio = =


Using (i)


=


Cross multiply


a =


Divide numerator and denominator by 2 we get


a = = = +


a = 1 + = 1 cups of milk



The ratio number of cups of milk to number of cups of flour is constant


When number of cups of milk is 1 number of cups of flour =


ratio = = = …(ii)


Let number of cups of flour required be ‘b’ when number of cups of milk are


ratio = = =


Using (ii)


=


Cross multiply


3b × 2 = 4 × 5


b =


Divide numerator and denominator by 2


b = = = +


b = 3 cups of flour


Therefore, cups of milk needed to make cake for 8 people is 1 and that of flour is 3


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