In a single row of yellow, green and red colored tiles....

[furtadovinod]

Here's a DS question for those who want to try it out

In a single row of yellow, green and red colored tiles, every red tile is preceded immediately by a yellow tile and every yellow tile is preceded immediately by a green tile. What color is the 24th tile in the row?

(1) The 18th tile in the row is not yellow.

(2) The 19th tile in the row is not green.

I want to know is there a similar question in the OG or is anyone aware of such a question coming in the GMAT Prep software? I am asking because this question tests nothing. Its more a trick question than anything else. I wonder if the GMAT actual tests such thinking process.

[sharath.nair]

I think I have seen such a question on a kaplan test. However, don't quote me on that. I could have seen it somehwere else.. :-)

Why cant this be a gmat question? You would really have stretch your thinking and spend time to test all cases before selecting E. (The answer is E right?)

[furtadovinod]

I think I have seen such a question on a kaplan test. However, don't quote me on that. I could have seen it somehwere else.. :-)

Why cant this be a gmat question? You would really have stretch your thinking and spend time to test all cases before selecting E. (The answer is E right?)

Hi Sharath,

Yes you are right (if I remember correctly). The reason why I think it cannot be a GMAT question is the same reason that you have given "You would really have stretch your thinking and spend time to test all cases before selecting E". Besides the fact that the OG does not seem to have a similar question, I cannot understand what topic is being tested here?

[supratims]

this is a valid GMAT question. I have seen very similar one in GMATPrep and in MGMAT tests as well.

[Ben Ku]

I think this kind of question could be on the GMAT. I don't think it's too cumbersome to figure out.

Basically, the tiles are arranged G - Y - R, in that order. If we know the color of any ONE tile in the row, then we can determine the 24th tile.

Because neither statements provide the information of any particular tile, then they by themselves are insufficient.

Looking at them together, Statement (1) says the 18th can either be red or green, and Statement (2) says that the 19th can be either red or yellow.

So the different arrangements for the 18th and 19th tiles are:
R - Y --> An invalid order
G - Y --> A valid order
G - R --> An invalid order

So therefore 18th must be Green, 19th must be Yellow, and the 24th must be Green. The answer is (C).

Examples of DS problems that require similar kind of logical thinking include (from the 12th Edition of the Official Guide) D45 and 130.

[furtadovinod]

I think this kind of question could be on the GMAT. I don't think it's too cumbersome to figure out.

Basically, the tiles are arranged G - Y - R, in that order. If we know the color of any ONE tile in the row, then we can determine the 24th tile.

Because neither statements provide the information of any particular tile, then they by themselves are insufficient.

Looking at them together, Statement (1) says the 18th can either be red or green, and Statement (2) says that the 19th can be either red or yellow.

So the different arrangements for the 18th and 19th tiles are:
R - Y --> An invalid order
G - Y --> A valid order
G - R --> An invalid order

So therefore 18th must be Green, 19th must be Yellow, and the 24th must be Green. The answer is (C).

Examples of DS problems that require similar kind of logical thinking include (from the 12th Edition of the Official Guide) D45 and 130.

Hi BKU,

Unfortunately, you are wrong. The answer is not (C) its (E). I will not go into the reasons. I think you can easily check it in the explanations.

On a side note, I know some have commented that such a question is possible in the GMAT. I am still not convinced, mainly because I reiterate it does not seem to be testing any fundamental topic. All it seems to be testing is if someone can realize that all the tiles could be green except the 19th and the 20th, where it needs to follow a sequence. Seems more like a trick to me. Like I said I could be wrong so if someone could actually post something similar from the official guides or GMAT Prep would be great.

[Ben Ku]

Hi furtadovinod,

Thanks for correcting me. Apparently I fell into the trap of an incorrect assumption easily made by test takers. Although the pattern G - Y - R holds, we don't know that every green is preceeded by a red. It could be, for all we know, G - G - G - Y - R.

For that reason (that we cannot establish a pattern), the answer is (E). I don't know whether the GMAT would word the question in a tricky way like this, but I do think these logic-type questions are fair game, like the problems I referenced in the 12th OG problem.

[jigar24]

Dear BKU,

The question clearly states EVERY red tile is preceded by yellow and that EVERY yellow by green..then why can't the patter hold all through?

[jnelson0612]

Dear BKU,

The question clearly states EVERY red tile is preceded by yellow and that EVERY yellow by green..then why can't the patter hold all through?

Yes, the exact words are "every red tile is preceded immediately by a yellow tile and every yellow tile is preceded immediately by a green tile."

BUT, we don't know what precedes a green tile!

We could have GGYR
or we could have
GGGGGGYR, for example. We have all sorts of possibilities of how many green tiles there are before Y and R.

Thus, to your question, the pattern *can* hold, but it does not HAVE to hold. And in Data Sufficiency, a sufficient statement is something that definitively answers the question. Thus, neither of these statements are sufficient, even together.