Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In a classroom there are 28 pupils. 19 pupils know to speak English ad 16 pupils speak French. Knowing that every children is speaking at least one language(English or French) find out the number of pupils who are speaking only English.


share|cite|improve this question
up vote 1 down vote accepted

Let $e$ denote the number of pure English speakers. Let $f$ denote the number of pure french speakers. Let $m$ denote the number of mixed speakers. Then we have the simultaneous equations $$\begin{align} m + e = 19 \\m + f = 16\\ m + f + e = 28\end{align}$$ From which you immediately get $e=12,\ f=9$ and $m=7$.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.