Chapter 3, Problem 3.48P

A block diagram of a linear circuit is shown in Figure P3-48. When $v_{\text{s}}=10\text{V}$ and $i_{\text{S}}=10\text{mA}$ the output voltage $v_{\text{O}}=1\text{V}\text{.}$ The output voltage is 2 V when the voltage source is $v_{\text{S}}=10\text{V}$ and the current source is off or $i_{\text{S}}=0\text{mA}\text{.}$ Find the output voltage when $v_s=20\text{V}$ and $i_s=-20\text{mA}\text{.}$