



 
Ali, I would use a tree diagram to analyze this question. Here is the structure of the tree I have in mind. From the question I can put probabilities on each branch. Juanita bumps into Tory with a probability of 0.25 and hence the probability that she doesn't bump into Tory is 1  0.25 = 0.75. If she bumps into Tory then the probability she is late for class is 0.45 and hence the probability that she is on time is 1  0.45 = 0.55. Similarly if she doesn't bump into Tory. Thus the tree with probabilities is I hope this helps,  


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