Answer:
The correct option is A.
27.1 is the closest to the average of the numbers in Group I and Group II combined.
Step-by-step explanation:
There is a set of 100 numbers.
- Half were selected to form Group I.
This means
Group I = 50 numbers
- 60 percent of the remaining numbers were selected to form Group II
This means
Group II = 0.6×50 = 30 numbers.
- Average of the numbers in Group I = 24.4
Total numbers = 24.4 × 50 = 1220
- Average of numbers in Group II = 31.5
Total numbers = 31.5 × 30 = 945
Therefore the Average of the numbers in Group I and Group II combined is
(1220 + 945)/(50 + 30)
= 2165/80
=27.06
This is approximately 27.1