The number of observations in a group is 40. The average of the first 10 members is 4.5 and the average of the remaining 30 members is 3.5. The average of the whole group is
A. 4
B. 15/2
C. 15/4
D. 6
Answer:C
The number of observations in a group is 40. The average of the first 10 members is 4.5 and the average of the remaining 30 members is 3.5. The average of the whole group is
A. 4 B. 15/2 C. 15/4 D. 6