Find the average of the first 20 multiples of 9.

Answer: Option B

First 20 multiple of 9

$$\begin{array}{rl}& \text{Average}=\frac{90+99}{2}\\ & =45+49.5\\ & =94.5\text{ Answer}\\ & \\ & \mathbf{Alternate}\mathbf{Solution}:\\ & \text{Average}=\frac{\text{First term}+\text{Last term}}{2}\\ & =\frac{9+180}{2}\\ & =4.5+90\\ & =94.5\end{array}$$