Correct Answer - D
Let the price of B per kg ₹ x. Then , the price of A per kg = ₹ 3 x
1 kg of C contains `2//7` kg of A and `5//7` kg of B
Price of 1 kg of C `= (2//7) xx 3x + (5//7) x = (11//7)x`
By the given condition, `11x //7`
`= 5.20 - 0.80`
`= ₹ 4.40`
`rArr x = 4.40 xx (7//11) = ₹ 2.80`
Hence the price of B per kg = ₹ 2.80.