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Question 1062127: A student scores 90% on a 20 question test. Use a percent equation to write the ratio of the actual number of questions answered correctly to the actual total number of questions. how do i do this?
Answer by math_helper(2461)   (Show Source):
You can put this solution on YOUR website!
Let P = the percentage score, expressed as percentage
Let c = number of correct answers
Let n = total number of questions
P = (c/n) * 100
[ "Percent" literally means "per 100" so given, say, 90%, you can also write that as 90/100 or 0.90 ]
In this specific question, number of correct answers = 90% * 20 = 0.90*20 = 18
So the score 90% = (18/20)*100
I hope this makes sense. Just remember that percent is the same as "per 100" and that people use it as a convenient way of scoring/measuring/quantifying things. Also, remember that given a value expressed as a percentage (i.e. with the % sign following the number) you can simply divide that number by 100 to convert to a decimal that you can use in your calculations.
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