Problem: The arithmetic mean (average) of a set of 50 numbers is 38. If two numbers, namely, 45 and 55, are discarded, the mean of the remaining set of numbers is:
Answer Choices:
A. 36.5
B. 37
C. 37.2
D. 37.5
E. 37.52
Solution:
Arith. mean = number of numbers sum of numbers
∴S=50×38=1900∴x=481900−45−55=37.5