Find the ratio in which rice at Rs.7.20 a kg be mixed with rice at Rs.5.60 a kg to produce a mixture worth Rs.6.30 a kg?
Choose the correct option: A) 1 : 3 B) 2 : 3 C) 3 : 4 D) 7 : 9 E) none of these

Rationale: "solution required ratio = 70 : 90 = 7 : 9 answer d"
Answer: D