PS ... Help.

[ramonsa]

7. A certain elevator has a safe weight limit of 2,000 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 180 pounds and the average weight of the others being 215 pounds?
(A) 7
(B) 8
(C) 9
(D) 10
(E) 11
Thanks

[vineetbatra]

average of first 50% is 180 average of the balance is 215

so totall average is

180*.5+215*.5 = 197.5

2000/197.5 = 10.1 so the answer is 10

what is OA

[nervesofsteel]

yes D for me too

180*(n/2)+215(n/2) = 2000
n = total number of people lift can carry..

n = 10.1

so ans 10