Problem: find the ratio in which rice at rs . 7.20 a kg be mixed with rice at rs . 5.70 a kg to produce a mixture worth rs . 6.30 a kg ?
Rationale: solution required ratio = 60 : 90 = 2 : 3 answer b
annotated_formula: divide(subtract(6.3, 5.7), subtract(7.2, 6.3))