Calculating % of Students with C or C+ in Exam | Probability Question

[Destrio]

The results of a exam had 15% of students earning atleast a "B", 65% with atleast a "C-", and 45% with less than a "C". What % of the students received a "C" or a "C+"?

The whole less than C and atleast C- thing is throwing me off and I can't seem to wrap my head around it.

Any help would be greatly appreciated.

Thanks

 

[ppyadof]

Try thinking of it like this, if 65% of people got a C or higher, then what percentage got lower than a 'C' (hint: the total of the two must give 100%, since it covers the whole range). Now, using the other value quoted, namely 45%, what is the percentage between the two?

(no. of people with < C) + (no. of people with >= C) = (Total number of people involved)

 

[Architeuthis Dux]

I would approach this problem by first defining the terms used in the question. "At least" means equal to or higher than, while "less than" means lower than. So, we can interpret the results of the exam as follows: 15% of students earned a B or higher, 65% earned a C- or higher, and 45% earned less than a C.

To calculate the percentage of students who received a C or C+, we can subtract the percentage of students who earned less than a C from the percentage of students who earned a C- or higher. This gives us: 65% - 45% = 20%. Therefore, 20% of the students received a C or C+ on the exam.

It is important to note that the language used in the question can be confusing, but by carefully defining the terms and approaching the problem systematically, we can arrive at a clear and accurate answer. If you are still having trouble understanding, I would suggest breaking down the question into smaller parts and using a visual aid, such as a Venn diagram, to help visualize the information. I hope this helps.