Q.In a survey of 150 small retailers in an Odisha district, 80 stock stationery items, 65 stock grocery items, and 30 stock both. Find

Add the two counts and remove the overlap once to avoid double-counting; subtract from the total to find the leftover group.

Step 1 — Identify the sets. $A$=stationery stockists, $n(A)=80$; $B$=grocery stockists, $n(B)=65$; $n(A\cap B)=30$. Total surveyed $=150$.

Step 2 — Apply the formula. $n(A\cup B)=80+65-30=115$.

Step 3 — Find the "neither" group. $150-115=35$. …

Building the only-A / only-B / both breakdown directly and summing is an indepen …

Simply adding $80+65=145$ and treating that as the final answer double-counts …