A grocer mixed sugar at 12 per kg with sugar at 9 per kg in a certain ratio and sold the mixture at 11 per kg to have a gain of 1/8th of his total investment. The ratio of two types of sugar in the mixture is

Selling price of mixture = Rs. 11/kg and gain = $$\frac{1}{8}$$

=> Cost price = $$\frac{11}{1+\frac{1}{8}}$$

= $$\frac{11\times8}{9}=Rs.$$ $$\frac{88}{9}$$

Let ratio of both types of sugar respectively be $$x:y$$

According to ques, 

=> $$12x+9y=\frac{88}{9}(x+y)$$

=> $$108x+81y=88x+88y$$

=> $$108x-88x=88y-81y$$

=> $$20x=7y$$

=> $$\frac{x}{y}=\frac{7}{20}$$

$$\therefore$$ The ratio of two types of sugar in the mixture = $$7:20$$

=> Ans - (A)