Question 1173542: There are _____ways that a student can answer the exam with 7 correct answers and 8 incorrect answers. Found 2 solutions by ewatrrr, ikleyn:Answer by ewatrrr(24785) (Show Source):
Hi,
There are _____ways that a student can answer the exam with 7 correct answers and 8 incorrect answers.
15 Questions: 7correct, 8 incorrect
Using Combinations (nCr) on Calculator:
Best not to over think it.
Yes, (15C7)= 6435 ways a student can answer the exam with 7 correct answers out of 15 questions. (others could have had no answer)
Wish You the Best in your Studies.
You can put this solution on YOUR website! .
There are _____ways that a student can answer the exam with 7 correct answers and 8 incorrect answers.
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It is assumed (although does not formulated explicitly in the problem) that there are 8+7 = 15 questions, in all.
There are ways to select 7 questions from 15 questions to answer them correctly.
The rest questions will be automatically answered incorrectly.
Your ANSWER is = = = 6435 ways.
Solved.
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Actually, the problem in the post is worded INCORRECTLY.
The correct wording is
There are 15 questions at an exam.
In how many ways the student may answer 7 questions of them correctly ?
I observe it very often at this forum that the "local composers" formulate their problems INCORRECTLY,
because they do not know the subject professionally.
