In what ratio must rice of Rs.54per kg be mixed with rice of Rs.35 per kg so that cost of mixture is Rs.42 per kg?	Choose the correct answer: A) 9 : 7 B) 7 : 12 C) 12 : 7 D) 5 : 6 E) 7 : 9

Rationale: ( 42 - 35 ) / ( 54 - 42 ) = 7 / 12 = 7 : 12 answer : b
Answer: B