Bunuel
If A = {products of 2 and an odd number} and B = {even multiples of 3}, which of the following numbers is in the intersection of A and B?
I. 6
II. 18
III. 30
A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III
Solution: Set A = {products of 2 and an odd number}. This means this set contains numbers like:
\(2\times 1=2\)
\(2\times 3=6\)
\(2\times 5=10\) and so on.
Set B = {even multiples of 3}. This means this set contains numbers like:
\(3\times 2=6\)
\(3\times 4=12\)
\(3\times 6=18\) and so on.
Now let us look into the numbers given to us:
1. 6: This will be in both sets. We can see above it is the \(2^{nd}\) element of set A and \(1^{st}\) of set B.
2. 18: This will also be in both sets. in set A there will be an element \(2\times 9=18\) (\(5^{th}\) element) and we see it is \(3^{rd}\) element of set B.
3. 30: This will also be in both sets. in set A there will be an element \(2\times 15=30\) (\(8^{th}\) element) and in set B there will be an element \(3\times 10=30\) (\(5^{th}\) element).
We see that all 3 numbers are in both sets.
Hence the right answer is
Option E.