Question

.
Let A = {x: x is positive integral 1 point
multiple of 3 less than 31} and B
= { x:x is prime number less
than 30), Then n(AUB) + n(ANB)
is equal to: *
020
O 21
O 10
O None of the above​

Answer 1

Answer:

20

Step-by-step explanation:

A=(3,6,9,12,15,18,21,24,27,30)

An= 10

B =(2,3,5,7,11,13,17,19,23,29)

Bn= 10

n(AUB)=An+Bn-n(A inter. B)

n(AUB) = 10+10-1

            =19

also     n(AUB)= An+Bn -n(AՈB)

n(AUB) + n(AՈB) = 19+1=20