venn diagram

Question

A survey is conducted among $275$ families. $100$ families among them use air condition (A.C.) $70$ families use only coolers, $60$ families use only AC and $80$ families use only fan. $10$ families use all three and $10$ families use none of these.

How many people use either a cooler or an AC?

• A. 185  
• B. 190
• C. 205  
• D. cannot be determined

Answer 1

180

Answer 2

using either AC or cooler : (Ac U cooler) = p(ac)+ p(cooler)-p(ac n ​​​​​​​​​​​​​​​cooler)

= 100+70-10=160

Hence option d is correct