Answer: 1
Step-by-step explanation:
Probability of Success = 0.4
Let (X) be the number of total successful serves she must practice continuously until she has 50 successful serves.
Therefore, to determine the successful practices to have 50 successful serves;
Probability of Success × (X) = 50
0.4 × X = 50
X= 50/0.4 ; X= 125
She MUST practice up to 125 serves to get the required 50 successful serves
Therefore, the probability that she need more than 100 serves to accomplish her goal = 1
METHOD 2
Probability = number of required outcomes / number of possible outcomes
Required outcome = >100 serves = 1
Possible outcomes = if she must serve at least 125 times to get 50 which means 1
Probably (P) = 1/1
= 1
