ANSWER
$20,000
Step-by-step explanation
We want to find how much Mr Crankshaft has to sell to make a commission of $1000.
Let the amount he sells be x.
Since the commission rate is 5%, it means that 5% of x must be equal to $1000 (his commission).
Therefore, we have that:
![\begin{gathered} (5)/(100)\cdot x=1000 \\ \Rightarrow x=(1000\cdot100)/(5) \\ x=\text{ \$20,000} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/u6nskff04fhuy3xj7ftnyx1wdk2izzi86e.png)
He has to sell $20,000.