A certain elevator has a safe weight limit of 1950 pounds. What is the greatest possible number of people who can safely ride on the elevator at one time with the average (arithmetic mean) weight of half the riders being 190 pounds and the average weight of the others being 200 pounds?  Choose one:
A) 7  B) 8  C) 9  D) 10  E) 11

Rationale: "lets assume there are 2 x people . half of them have average weight of 190 and other half has 200 . maximum weight is = 1950 so 190 * x + 200 * x = 1950 = > 390 x = 1950 = > x is approximately equal to 5 . so total people is 2 * 5 = 10 answer d ."
Answer: D