Hi guys! I have a real life math problem and I would love your help and advice in understanding how it works.

I'm making a course for people who want to take an English exam, and I'd like to know about the size of the market. But the company who make the exam don't release the number of students taking the exam. So I need to estimate! Luckily I do have a list of data, organised by country, which shows the percentage of students in each country who got each grade (A, B, C, D and Fail).

I would like to know the minimum possible number of students in each country, given those percentages, who took the exam in 2016.

You can find the orginal list http://gradestatistics.cambridgeenglish.org/2016/fce.html.

And this is an example of a line of data from the table:

Albania Grade A: 13.2% Grade B: 19.4% Grade C: 43.2% Grade D: 18.9% Fail: 5.3%

Given these percentages, how can I calculate an estimate for the lowest possible number of students who took the exam in Albania?

I would love to know the method for finding this out so I can a) learn some maths and b) do the calculations myself.

Thanks so much for your help!

Sam