Answer
See below.
Work Step by Step
By definition, the expected value is the sum of each outcome multiplied by its probability.
Hence here the expected value: $\frac{10}{20}\cdot(1-20)+\frac{5}{20}\cdot(2-20)+\frac{3}{20}\cdot(5-20)+\frac{1}{20}\cdot(10-20)+\frac{1}{20}\cdot(100-20)=-12.75$.
This means that in the long run a player is expected to lose $12.75$ each turn he plays on average.
