A class has 175 students. The following data shows the number of students obtaining one or more subjects. Mathematics 100, Physics 70, Chemistry 40; Mathematics and Physics 30, Mathematics and Chemistry 28, Physics and Chemistry
18. How many students have offered Mathematics alone?
Show Hint
To find the number of students offering only one subject, use the inclusion-exclusion principle.
Step 1: Use the principle of inclusion-exclusion.
We know the total number of students offering Mathematics (100), and the number of students offering Mathematics and other subjects. Using inclusion-exclusion:
\[
\text{Mathematics alone} = \text{Mathematics total} - (\text{Mathematics and Physics}) - (\text{Mathematics and Chemistry}) + (\text{Mathematics, Physics and Chemistry})
\]
\[
\text{Mathematics alone} = 100 - 30 - 28 + 18 = 60
\]
Final Answer:
\[
\boxed{60}
\]