Let set C = {even numbers between 1 and 99} and set D = {numbers between 1 and 150 that are evenly divisible by 10}.

What is C ∩ D?

@ganeshie8,

In case of Set C the possible set is {2,4,6, ... 98} and in case of Set D, the possible set is given by { 10, 20, 30, ... 150}. Now C ∩ D means the set that is common to both C and D. Let's name the set as E. Hence Set E will have {10,20,30,40,50,60,70,80,90} Hence there are 9 observations which are common to both Set C and Set D.