In what ratio must rice of Rs.30 per kg be mixed with rice of Rs.56per kg so that cost of mixture is Rs.35 per kg? Choose the correct choice from the following answers: A) 28 : 15 B) 6 : 7 C) 7 : 6 D) 5 : 21 E) 21 : 5

Rationale: "( 35 - 56 ) / ( 30 - 35 ) = 6 / 2 = 21 : 5 answer : e"
Answer: E