Elementary Statistics (12th Edition)

a) The probability of guessing an answer correctly is $\frac{1}{5}$ and of gussing incorrectly is $\frac{4}{5}$. Therefore the probability:$P(WWC)=\frac{4}{5}\cdot \frac{4}{5} \cdot \frac{1}{5}=0.128.$ b) The good possibilities are WWC, WCW and CWW and each of them have the same probability of 0.128. c) Using b), the probability of getting exactly 1 correct answer out of 3 is $3\cdot 0.128=0.384$.