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?
using either AC or cooler : (Ac U cooler) = p(ac)+ p(cooler)-p(ac n cooler)
Hence option d is correct