A farmer has an apple orchard consisting of Fuji and Gala

[ani.ju.it]

I think I will try this as classical overlapping set problem.

| F | NF
----------------------
G | x/10 | 33 |

NG | 3x/4 | 0 |
-----------------------------
| 187 | 33 |X = 220

Assume x is the total number here

x/10 + 3x/4 = 187

solving it

x = 220

Now I can put the value back into the grid

There are no category for NG and NF so it goes as 0.

As the question asks for pure Gala so the category is G + NF

So the answer is 33.Though it is not the fastest way to do,it is one way to put it systematically.

[jnelson0612]

:-) Thanks!

[asharma8080]

I tried solving this using 2x2 matrix.

Mutually exclusive sets in this case are :
Fuji trees / Not Fuji
And
Gala Trees / Not Gala Trees Trees
F NF T
G 0.1T x
NG (3/4)T 0
---------------------------------
T 187 x T

trying to find x

0.1 T + 0.75 T = 187
0.85T = 187
T = (187) / (.85) = 220

Key was recognizing the hidden constraint that there are no trees that are NOT Fuji AND also NOT Gala. There are only three types of trees, Fuji, Gala and Fuji + Gala.

So, x = T - 187 = 220 - 187 = 33

[tim]

let us know if there are any further questions on this one..

[nocheivyirene]

3/4 of Trees = F
1/10 of Trees = C
1 - 3/4 + 1/10 = 1 - 17/20 = 3/20 = G

F + C = 187 = 17/20T

G = 187 (20/17)(3/20) = 187 (3) / 17 = 33

Answer: B

[jlucero]

Correct.

[nishatfarhat87]

Also, the question talks about 10% trees having pollinated after mentioning that the farmer's orchard consisted of Fiji and Gala trees. Following that line, it's pretty clear that 10% of THOSE (F+G) cross pollinated.

Regards,
N

Right, but remember that the original F + G equals the same number of the later F + G + C. You are just taking some of the original F + G and converting them to C.

I confused "10% of his trees cross pollinated" with the act of cross pollinating and hence that would give me no idea about the results of these cross pollinated trees i.e the no. of trees that are F/G. Do we get such ambiguous language questions on the real GMAT?

[StaceyKoprince]

Please note that this thread contains the OLD text of the question (if you scroll back, you will see that people raised issues about this one several years ago).

This question no longer exists in this form in our CATs. The new question text is below. Note that it now spells out what "cross pollinated" means. :) Try it out!

A farmer has an apple orchard consisting of Fuji and Gala apple trees. Due to high winds this year 10% of his trees cross pollinated, creating trees that are part Fuji and part Gala. The number of his trees that are pure Fuji plus the number that are part Fuji and part Gala totals 187, while 3/4 of all his trees are pure Fuji. How many of his trees are pure Gala?


A 22
B 33
C 55
D 77
E 88

[dips]

I think the problem with the wording of this question is that none of us know enough biology to know whether cross pollination results in new trees or just changes the original tree to hybrid one.

Even with the new text, the language is ambiguous. I wasted so much time on this question because of the wording, since I felt the question was too easy

[RonPurewal]

Does your test contain the version quoted in Stacey's post (directly above yours)?

If so, the term "cross-pollinated" is defined in the second half of that same sentence.

[RonPurewal]

Also, don't forget that the GMAT NEVER contains "trick questions".
Nor does it ever contain questions requiring specific, relatively uncommon knowledge.
Never. Never ever ever.

If the only tree types mentioned are "pure Fuji", "pure Gala", and "mixed", then those are the only types. Period.

There will NEVER be unmentioned but existing "other types" relevant to the problem, unless their existence is absolutely universal knowledge. As in "every Earthling over the age of 7 would know this".
E.g., if a problem mentions redheaded and blond individuals in a room, but doesn't say that they're the only people in the room, then it's reasonable to expect test takers to think about people with dark/black hair. Because everyone knows that such people exist.