Question

The arithmetic mean of 4 items is 5 and arithmetic mean of 5 items is 10 . The combined arithmetic mean is

• A. 7
• B. 8.5
• C. 7.78
• D. 9.2

Answer 1

Answer:

C. 7.78

Arithmetic mean of 4 items is 5 Sum = 4 × 5 = 20 Arithmetic mean of 5 items is 10 Sum = 5 × 10 = 50 Mean = total/number = (20 + 50)/9 = 70/9 = 7.78