Q. 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 $23$; Mathematics, Physics and Chemistry $18$. How many students have offered Mathematics alone?
BITSATBITSAT 2013
Solution:
$n (M$ alone)
$=n(M)-n(M \cap C)-n(M \cap P)+n(M \cap C \cap P)$
$=100-28-30+18=60$
