Mike got a score of 56 on a recent 25-question multiple choice test. The scoring for the test was +6 for each correct answer, -2 for each incorrect answer and 0 for each unanswered question. What is the maximum number of questions Mike could have answered correctly?
My book says the answer is 13 but I'm not sure how to calculate this.
the maximum point is 150 (6*25)
He got
that is
so he had somehow minus 94 points from the maximum.
Each wrong answer gives you minus 8 points from the maximum points.
(-6 for not getting it correct and the minus 2 for answering wrong).
So the question is now.
How many questions can go wrong and still get 56 points?
The answer is
so 12 questions can go wrong and u can still get 56 points.
That leaves you with 25-12 = 13
Understandable?
Regards Henry
Hello, donnagirl!
Mike got a score of 56 on a recent 25-question multiple choice test.
The scoring was: +6 for each correct answer, -2 for each incorrect answer,
and 0 for each unanswered question.
What is the maximum number of questions Mike could have answered correctly?
Let: .
We have: ..[1]
and: ..[2]
Add [1] and [2]: .
Sinceis an integer,
must be divisible by 4.
The first time this happens is when
. . Hence: .
There are other values of
. . but they produce smaller values of
Therefore, Mike could have had a maximum of 13 right answers.
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