Question

Kim has a strong first serve; whenever it is good (that is, in) she wins the point 80% of the time. Whenever her second serve is good, she wins the point 60% of the time. Sixty percent of her first serves and 90% of her second serves are good. What is the probability that Kim wins the point when she serves?

Answer 1

i have now read this many 5 times and it is confusing so lets try this
lets say she plays 100 games and see

Answer 2

Its a tree diagram question is that helps

Answer 3

60% of her first serves are good, so 60 are good

Answer 4

and she wins the point 80% of those times so she wins the point \(.6\times 80=48\) times

Answer 5

A) What is the probability that Kim wins the point when she serves

Answer 6

i guess i am confused because i don't know the rules

Answer 7

B)The probability the Kim's first serve is good if she wins the service point is

Answer 8

then what about the second serve? are we to assume she gets a second serve only if she misses the first? or doesn't win the point on the first serve? i am confused by this

Answer 9

in other words, of the 40% that are not good, does she then get a second serve?