The average of 5 quantities is 6. The average of 3 of them is 4. What is the average of the remaining two quantities?
Answer: C
Total sum of the 5 quantities = 5 × 6 = 30.
Sum of 3 of these quantities = 3 × 4 = 12.
Sum of the remaining two quantities = 30 - 12 = 18.
Average of the remaining two quantities = \(\frac{18}{2} = 9\).