Question

A=(x:x is a prime factor of 30) and B={x:x isa prime factor of 20)

Find AUB and A intersection B

Answer 1

prime factors of 30 = 2,3,5
therefore
A ={ 2,3,5}
prime factors of 20= 2,2,5
therefore
B = {2,5}
therefore
A U B = {2,3,5}
and
A Intersection B = {2,5}

Answer 2

A={2,3,5}
B={2,5}
A UB={2,3,5}=A
A intersection B={2,5}=B