Question 64

The average of 21 numbers is 12. The average of the first 11 numbers is 9 and the average of the last 11 numbers is 15. What is the value of the middle number?

Solution

Average of 21 numbers = 12

=> Sum of 21 numbers = $$21 \times 12=252$$

Similarly, sum of first 11 numbers = $$11 \times 9=99$$

Sum of last 11 numbers = $$11 \times 15=165$$

$$\therefore$$ Value of the middle number = $$(99+165) - 252 = 264-252=12$$

=> Ans - (C)

Share on Whatsapp Share on Whatsapp

Create a FREE account and get: