In this question choice A seems right as well because despite the fact that question says “both” it also say contains “all” elements from both sets and clearly choice A satisfies that(since all elements from both sets are present there as well). However, if the question were to say “only” then the explained solution would have made sense. The current choice which is D is not wrong but its not the only right choice.

Comments ?

its a LCM question in disguise.

I think if it was both A **or** B then your logic would be the right answer

A has 2 → Now, 4 is a multiple of 2 and not the other way round, so A could never be the answer!

I understand what question creator had in mind while framing the question and I understand your reply as well @HoldMyBeer that its an LCM question in disguise(for sure an attempt).

However, a rotten word changes what purpose the question actually fulfills: “Which set below consists of all elements from both A and B” ?

Lets take answer choice A. (2, 4, 6, 8…)

Does it contain all elements which are multiples of both 4 and 6 - Yes it does.

Then, is it a set which contains all elements from both A and B? - Yes (Please note it contains 12, 24 etc… plus some other elements)

Regarding focus on “or” its not required to justify choice A.

Please note that I understand that why D is answer but A is good as well because it doesnt need to contain “only common multiples like 12” it can very well have many other numbers. As long as it has the required numbers(12, 24, 36…), it will still satisfy this question’s requirements to be a valid answer, even if it contains other elements as part of the set !

2 is neither a multiple of 4 or 6

the first multiple of 4 is 4 and the first multiple of 6 is 6.

It doesn’t need to be because as long as set contains (12, 24, 36…) along with other elements like (2, 10… etc) it still qualifies as a set which “consists of **all** elements from both…”

I guess this might be going in circles after this point, so will avoid repetition on the same point ! But, I am totally with author’s mindset to device problem testing LCM in a unique way !

Thanks for your thoughts and engaging discussion @HoldMyBeer !

Set B is {4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92,96}

Set A is { 6, 12, 18, 24, 30, 36 , 42, 48, 54, 60, 66, 72, 78, 84, 90, 96}

So, when question ask all elements from both A and B . There is no chance it contains a 2. Thus, A is wrong.

if the question were to say “only” then the explained solution would have made sense.

And that’s why the question has been fixed - thanks for reporting.

Anonymous:if the question were to say “only” then the explained solution would have made sense.

And that’s why the question has been fixed - thanks for reporting.

Thanks for fixing !