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?
Choose the correct choice from the following answers:
A) 1 : 3
B) 9 : 4
C) 8 : 7
D) 11 : 9
E) 11 : 7

Rationale: 9.30 x + 10.80 y = 10 ( x + y ) . 80 y = . 70 x x / y = 8 / 7 c is the answer
Answer: C