A business man buys two qualities A and B of a product at Rs. 120 per kg and Rs. 60 per kg respectively. He then mixes these two qualities and sells at Rs. 100 per kg. Then the percentage increase in the profit on a certain quantity of the mixture of A and B in the ratio 7 ∶ 11 on the profit on the same quantity of the mixture of A and B in the ratio 1 ∶ 1, is
1
\(\frac{80}{9}\)
2
\(\frac{80}{7}\)
3
\(\frac{75}{8}\)
4
\(\frac{200}{3}\)