Question

Let X={a,b,c,d} and Y={1,2,3,45,6}.How many functions from X to Y contain (a,1) or(b,2) or both?

Comments

for (a,1) number of functions are (6)³------------- as for b,c, and d we can select from 1,2,3,4,5,6

for (b,2) number of functions are (6)³--------------same as above

for both ,number of functions are (6)² as c and d can choose from 1,2,3,4,5,6