To train for a race, Scott wants to run 20 miles this week. He runs 14 of the miles on Monday.
2 answers:
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Answer:
Step-by-step explanation:
Let's write out a case for two specific questions being correct and the rest being incorrect:
,
The represents the chances of getting the question correct, as there are 5 answers and 1 correct answer choice.
The represents the chances of getting the question incorrect, as there are 5 answers and 4 incorrect answer choices.
The equation above does show the student getting two answers correct and three answers incorrect, but it only shows one possible case of doing so.
We can choose any two of the five questions to be the ones the student gets correct. Therefore, we need to multiply this equation by the number ways we can choose 2 from 5 (order doesn't matter): .
Therefore, the probability the student gets two questions correct is: