In a survey of 220 students of a higher secondary school, it was found that at least 125 and at most 130 students studied Mathematics; at least 85…

In a survey of $\displaystyle 220$ students of a higher secondary school, it was found that at least $\displaystyle 125$ and at most $\displaystyle 130$ students studied Mathematics; at least $\displaystyle 85$ and at most $\displaystyle 95$ studied Physics; at least $\displaystyle 75$ and at most $\displaystyle 90$ studied Chemistry; $\displaystyle 30$ studied both Physics and Chemistry; $\displaystyle 50$ studied both Chemistry and Mathematics; $\displaystyle 40$ studied both Mathematics and Physics and $\displaystyle 10$ studied none of these subjects. Let m and n respectively be the least and the most number of students who studied all the three subjects. Then $\displaystyle \mathrm{m}+\mathrm{n}$ is equal to $\displaystyle \_\_\_\_$.