Question 1044173: Q: Brittany plans to take Pre-Calculus, English 12, Physical Education, Economics, and Anthropology in her senior year. She hopes to have Pre-Calculus and Physics in the morning. What is the probability that her first two classes will be Pre-Calculus or Physics? Stephanie solves the problem incorrectly. In which line does she FIRST make an error?
line 1: P(6,2) = 6!/4! = 30
line 2: P(6,4) = 6!/2! =360
line 3: P (6,2) * P(6,4) = 30*360=10,800
line 4: P(6,6) = 6!/0! - 720
line 5: s/s+f = 720/10,800 = 66.7 %
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Assuming I interpret the question properly, line 1 is the first line where she goes astray. The question is probability, and she begins with a combinatorial. She has to begin with something probabilistic, and one way to do that is to say it is a probability of 1 over a combinatorial.
Also, physics wasn't included in the list. This was probably a typographical mistake, but if not, then line 1 is the first combinatorial with a 6, where it should be a 5.
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