Answer
Venn diagram
Work Step by Step
(a)
The number of American adults who invested only in stocks is represented by region I:
\[\begin{align}
& \text{Number of adults who invested only in stocks}=n\left( \text{I} \right) \\
& =250
\end{align}\]
(b)
The number of American adults who invested in stocks or bonds is represented by the sum of the regions I, II, and III:
\[\begin{align}
& \text{Number of adults who invested only in stocks or bonds}=n\left( \text{I} \right)+n\left( \text{II} \right)+n\left( \text{III} \right) \\
& =250+400+150 \\
& =800
\end{align}\]
(c)
The number of adults who did not invest in either stocks or bonds is represented by region IV:
\[\begin{align}
& \text{Number of adults who did not invest in either stocks or bonds}=n\left( \text{IV} \right) \\
& =200
\end{align}\]
