In what ratio should a variety of rice costing Rs. 5.5 per kg be mixed with another variety of rice costing Rs. 8.75 per kg to obtain a mixture costing Rs. 7.50 per kg? Choose the correct choice from the following options
A) 5/6  B) 5/9  C) 5/1  D) 5/8  E) 7/6
Let us say the ratio of the quantities of cheaper and dearer varieties   = x : y   By the rule of allegation, x/y   = (8.75 - 7.50) / (7.50 - 5.5) =5/8   Answer: 5/8
<result>D</result>
In what ratio should a variety of rice costing Rs. 5.5 per kg be mixed with another variety of rice costing Rs. 8.75 per kg to obtain a mixture costing Rs. 7.50 per kg?