The answer for your question is B: Formal
Well you could solve by cross multiplying 66 and 2/3 (into an improper fraction) multiplied by the reciprocal of 30, but 66 and 2/3 means 2/3 (1/3 equals 33 1/3 %) so then you can divide 30 by 3, which is 10, and then multiply by 2 to get 20. So, 66 and 2/3 of 30 is 20. Hope that helped!
