Gwen, a friend of Mary from the previous question, is also practicing free throws. However, she is trying to score 3 points in a single set. She will keep shooting sets until she has three successful shots in a single set. Gwen is more confident in her abilities, and believes that she can successfully make any single shot with a probability of 0.8.

Give your answer as a decimal to 4 decimal places.

a) Given the information above, how many sets does Gwen expect to make?