The average of 7 consecutive numbers is 20. The largest of these numbers is-

Answer: Option C

Let the number be x, x + 1, x + 2, x + 4, x + 5 and x + 6
Then,
$$\Rightarrow \frac{x+\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+\left(x+4\right)+\left(x+5\right)+\left(x+6\right)}{7}=20$$
$$\begin{array}{rl}& \Rightarrow 7x+21=140\\ & \Rightarrow 7x=119\\ & \Rightarrow x=17\end{array}$$

∴ Largest number
= x + 6 = 17 + 6
= 23