19. From a set of 100 numbers, half were selected to form group I, and 60 percent of
the remaining numbers were selected to form group II. The average (arithmetic mean)
of the numbers in group I is 24.4, and the average of the numbers in group II is 31.5.
Which of the following is closest to the average of the numbers in groups I and II
combined?
the remaining numbers were selected to form group II. The average (arithmetic mean)
of the numbers in group I is 24.4, and the average of the numbers in group II is 31.5.
Which of the following is closest to the average of the numbers in groups I and II
combined?
A. 27.1
B. 27.6
C. 27.8
D. 28.0
E. 28.3
B. 27.6
C. 27.8
D. 28.0
E. 28.3
답은 A 라고 합니다. 그룹 1과 그룹2의 평균을 %로 배분해서 풀어야할것 같은데... 정확한 접근 방법을 모르겠네요.
부탁드립니다. 감사합니다.