Pie Charts Questions

The pie chart shows the breakdown of students who appeared for the exam across different sections. Total appeared = 1000. Section A represents 20% and Section B represents 25%. Find the difference between the number of students who appeared for the exam in sections A and B.

In a distribution of students in a town, the total number of graduate students is $27300$ and institute S comprises $21\%$ of them. The total number of post-graduate students is $24700$ and institute S comprises $19\%$ of them. What is the ratio between the number of students studying at post-graduate and graduate levels respectively from institute S?

The data indicates the distribution of students across seven different institutes (P, Q, R, S, T, U, V). In a standard evaluation of this problem where the total number of graduate students is $27300$ (with R comprising $18\%$) and post-graduate students is $24700$ (with R comprising $13\%$), what is the total number of graduate and post-graduate level students in institute R?