In what ratio must rice at $9.30/kg be mixed with rice at $10.80/kg so that the mixture is worth $10/kg?  Select the correct option.
A) 1:3 B) 9:4 C) 8:7 D) 11:9 E) 11:7
9.30x + 10.80y= 10(x+y)   .80y= .70x   x/y= 8/7   8:7 is the answer
<result>C</result>
In what ratio must rice at $9.30/kg be mixed with rice at $10.80/kg so that the mixture is worth $10/kg?