Concept: The question tests on Probability
Solution:
Here the wording is a little tricky. It asks us what is the probability of winning at least $50 (It does not ask what is the probability of winning at least the $50 prize)
To get at least $50, she can either win the $50 prize or the $100 prize (As she has only 1 ticket)
Favorable outcomes = 2
Total outcomes = 200C1 = 200 (We are choosing 1 raffle ticket winner among the 200 possible tickets)
Probability = Favorable Outcomes / Total Outcomes = 2 / 200 = 1/100
Option B