Question

The average of seven numbers is 6. What is the eighth number to be added to increase the average to 10?

• A. 28
• B. 38
• C. 48
• D. 58

Answer 1

The correct option is B 38

$\text{Let the eighth number to be added be x.}\therefore \text{Sum of seven numbers having an average of 6}=7\times 6=42\text{And sum of eight numbers having an average of 10}=10\times 8=8042+x=80\Rightarrow x=80-42\Rightarrow x=38\therefore \text{The required eighth number is 38.}$