Three hundred multiples of three are picked at random, and three hundr

Question

Three hundred multiples of three are picked at random, and three hundred multiples of four are picked at random. Approximately what percentage of the six hundred selected numbers are even?

A. 100%
B. 75%
C. 66%
D. 50%
E. 33%

goforgmat · Answer

all multiples of 4 are even
out of the 300 multiples of 3 no of even numbers= 0.5 *300=150
300+150/600= 75%

so b?

Harish Yannam · Answer

answer b. 100% multiples of 4 are even and 50% multiples of 3 are even.
these makeup 75% of all 600 multiples of 3 & 4 respectively.

Argo · Answer

I'd go with D.

Since the selection for both the multiples is random, the selection of all the three hundred multiples of three may be odd or even or a combination of both.

So, in the worst case (with all the odd multiples of three), 50% of the total selected is even.

abhimahna · Answer

I am a bit confused in this question. Since, we are given multiples are chosen at random, it may happen that all the multiples of 3 chosen are EVEN or ODD or Mixture.

Hence, we will get different answers each time.

Bunuel , kindly help.

testprepabc · Answer

When we say that the probability of getting a Heads in a single coin toss is 1/2, it implies that if the task is repeated for a great many number of times, chances are that we will get Heads half the times. Similarly, here we can observe that the possible chances of picking even multiples of 3 becomes 1/2 as every 2nd multiple is even. Example: 3, 6 , 9, 12 , 15, 18 etc Hope it helps

abhimahna · Answer

No, that I know. My concern here is you are assuming that the multiples of 3 are consecutive which is not given in the question.

We can have multiples of 3 like 3,9,15 and so on.

KS15 · Answer

300 multiples of 4-all will be even
Now, with multiples of 3, we have 3,6,9,12-so every alternate multiple of 3 is even-so total multiples of 3 in 300 numbers=150
So total even multiples of 3 and 4=300+150=450
Answer=450/600=75% C

pravinsinghkumar · Answer

Question seems incomplete 
Answer can be 50% or 75 % or 100%

chetan2u · Answer

Hi 
Bunuel may be further able to clarify the wordings but my take..

The word APPROXIMATELY tells us that we may be talking of probability too...
So in 300 randomly picked multiples of 3, probability that they are even is 50%, so 150 and all 300 multiples of 4 will be even, thus 75%...

Had word APPROXIMATELY not been used, the Q would be clearly missing the answer and would be insufficient

testprepabc · Answer

We are not assuming that only consecutive multiples are considered for this example.
Let me clarify. Choosing only odd multiples is one of the myriad possible scenarios. Let's say we have to choose only 2 multiples of 3. Someone picks 3 & 27. Someone else picks 6 and 9. Someone else 3 and 60. So on and so forth. What we observe here is when an infinite number of such samples are considered, 50% of them will have even multiples and 50% will have odd multiples because every 2nd multiple of 3 is even. As is the case with a coin toss, a person may get 100 Heads in a row, but when more samples are considered, the chances get closer to 1/2.

abhimahna · Answer

I donot agree with you. Its just to convince oneself when the OA is presented. Had the OA absent, you would also have looking for the right answer. Sorry Mate, but I think we need to wait for Bunuel to get the clarity on this question. Yes, I understand your point. But even if you take all multiples of 3 as ODD, you will get the answer as 50% which is also present in the options. Had the other possibility answers not present in options, we could have considered 75% and moved on. Lets wait for Bunuel now :-D

Argo · Answer

Can you please explain??

What if all the three hundred multiples of 3 which were picked at random were odd?

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Three hundred multiples of three are picked at random, and three hundr

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