49 Kg of blended tea contain Assam and Darjeeling tea in the ratio 5 : 2. Then the quantity of Darjeeling tea is to be added to the mixture to make the ratio of Assam to Darjeeling tea 2 : 1 is

solution

given 49 kg of tea  

Assam tea : Darjeeling tea = 5: 2

quantity of Assam tea = $$\frac{5}{7} \times$$49 = 35kg

quantity of Darjeeling tea =$$\frac{2}{7} \times$$49 = 14kg

In order to make the ratio of Assam tea : Darjeeling tea = 2: 1

present quantity of Assam tea = 35kg 

divide it by 2 we get 17.5 { The required quantity}

quantity  of Darjeeling tea at present = 14kg 

required quantity is 17.5 kg

amount to be added = 17.5 - 14 = 3.5 kg