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805+ (Hard)|   Math Related|         
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guddo
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An inventory of a neighborhood's trees found that 32 percent were 31 Jan 2026, 10:03
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Puranjaysapra
Thanks for responding. If I was to use the same logic, I also don't know the exact % of D trees as it says most of it implying that it could be anything less than 68%. I can determine that conifers will be more than spruces


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“Most deciduous” being vague does not matter, because the ratio uses only the deciduous group:

Japanese maples = 20% of (1/8 of deciduous) = 1/40 of deciduous, so the ratio is fixed.

For spruces vs conifers, total conifers is unknown (spruces + pines + unknown cedars/others), so 258 divided by total conifers is not fixed, even though conifers > spruces.

I'd advice checking for complete solutions these posts:

  1. https://gmatclub.com/forum/an-inventory ... l#p3373108
  2. https://gmatclub.com/forum/an-inventory ... l#p3368922
  3. https://gmatclub.com/forum/an-inventory ... l#p3362649
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An inventory of a neighborhood's trees found that 32 percent were 31 Jan 2026, 10:06
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Understood, Thank you! This is helpful
guddo


“Most deciduous” being vague does not matter, because the ratio uses only the deciduous group:

Japanese maples = 20% of (1/8 of deciduous) = 1/40 of deciduous, so the ratio is fixed.

For spruces vs conifers, total conifers is unknown (spruces + pines + unknown cedars/others), so 258 divided by total conifers is not fixed, even though conifers > spruces.

I'd advice checking for complete solutions these posts:

  1. https://gmatclub.com/forum/an-inventory ... l#p3373108
  2. https://gmatclub.com/forum/an-inventory ... l#p3368922
  3. https://gmatclub.com/forum/an-inventory ... l#p3362649
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An inventory of a neighborhood's trees found that 32 percent were 02 Feb 2026, 06:07
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Conifer = 32%
Deciduous can be maximum ~68% (let it be 68%)
1/8 are Maple = ~8.5%
20% of Maple are Japanese Maple = ~1.7%

We are sure that conifers are 32% and Japanese Maple can be max 1.7%, so why it may not be Japanese Maple and Conifers?
We are not sure of deciduous also, it can be anywhere between a little more than 34% to almost 68%.

Can someone pls explain?
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An inventory of a neighborhood's trees found that 32 percent were 13 Feb 2026, 02:35
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wouldn't conifers be more than spruces hence their ratio will be less than 1 despite of not knowing total of conifers we do know it is greater than spruces ?
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An inventory of a neighborhood's trees found that 32 percent were 13 Feb 2026, 04:22
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1111fate
wouldn't conifers be more than spruces hence their ratio will be less than 1 despite of not knowing total of conifers we do know it is greater than spruces ?
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No.

To select a valid pair, the ratio must be numerically determined, not just known to be less than 1.

It’s true that Conifers > Spruces, so Spruces/Conifers is less than 1. But we do not know how many cedars and other conifers there are, so we cannot compute the exact ratio.

Since the problem requires that the ratio “can be determined,” simply knowing it’s less than 1 is not enough.
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An inventory of a neighborhood's trees found that 32 percent were 13 Feb 2026, 04:32
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forestmayank
Conifer = 32%
Deciduous can be maximum ~68% (let it be 68%)
1/8 are Maple = ~8.5%
20% of Maple are Japanese Maple = ~1.7%

We are sure that conifers are 32% and Japanese Maple can be max 1.7%, so why it may not be Japanese Maple and Conifers?
We are not sure of deciduous also, it can be anywhere between a little more than 34% to almost 68%.

Can someone pls explain?
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Your calculation shows only a maximum. That’s the issue.

Conifers are fixed at 32% of all trees.

Japanese maples are 20% of maples, and maples are 1/8 of deciduous, so Japanese maples = 1/5 * 1/8 of deciduous = 1/40 of deciduous.

But deciduous is not fixed as a percent of all trees. It can be anywhere from just over 34% up to 68%. So Japanese maples as a percent of all trees can be anywhere from just over 34%/40 to 68%/40, i.e. just over 0.85% up to 1.7%.

Therefore Japanese maples/Conifers is not a single value. It could be just over 0.85/32 or it could be 1.7/32 or anything in between. The problem requires the ratio to be determinable (one exact number), not just bounded.
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An inventory of a neighborhood's trees found that 32 percent were 13 Feb 2026, 05:23
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Thanks Bunuel It's clear now :)
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An inventory of a neighborhood's trees found that 32 percent were 22 Aug 2026, 11:53
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Want to find a ratio that can be found using the answers provided and is less than 1.
I think it's easier to look at the options and eliminate obvious ones that use language like "most" and "some" because it will eliminate the host group as an option.

The two answers that give exact ratios are the maples-to-deciduous which =1/8 and the Japanese maple-to-deciduous which is 1/5.
The question wants to us to tell it the proper ratio and since the Japanese maples are a sub group of deciduous, they obviously are less than the deciduous group as a whole.
A:B=A/B<1, A= Japanese maple, B= Deciduous
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­An inventory of a neighborhood's trees found that 32 percent were conifers and most of the rest were deciduous. Among the conifers were 258 spruces and 112 pines, along with some cedars and other species. Most of the deciduous trees were oaks, but one in eight was a maple. Of the oaks, 65 percent were red oaks and 25 percent were white oaks. Of the maples, 20 percent were Japanese maples.

Select for A and for B two types of trees such that the ratio of the number of trees of the type selected for A to the number of trees of the type selected for B can be determined and is less than 1. Make only two selections, one in each column.­
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An inventory of a neighborhood's trees found that 32 percent were 08 Sep 2026, 09:51
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Reading & making the tree diagram itself is taking more than 2 mins !!! :(
chetan2u
Again a great question. can be done in exactly 30 seconds if understood well.­

The question wants us to find a ratio that is determinable, so let us see each statement. Working on options directly would be a faster way.

­An inventory of a neighborhood's trees found that 32 percent were conifers and most of the rest were deciduous.
We can just say that deciduous are anything greater than (100-32)/2 or >34 and \(\leq 100-32\)
Thus, no ratios can be found between conifers or its subpart and deciduous or its parts.

Among the conifers were 258 spruces and 112 pines, along with some cedars and other species.
We can find ratio between spruces and pines but nothing with total conifers or any other of its subparts.

Most of the deciduous trees were oaks, but one in eight was a maple.
Again use of 'most' restricts anyratio between deciduous and oaks or its sub parts. However ratio between deciduous and maple is given as 8:1.

Of the oaks, 65 percent were red oaks and 25 percent were white oaks. Of the maples, 20 percent were Japanese maples.
Ratio between Red oaks and white oaks is given but this cannot be connected to any other parts.
Also, Ratio between Japenese maples and total maples is given as 1:5

The ratios known are given in bold above
between spruces and pines....... Spruce is given in option but pine is not.
between deciduous and maple...... Deciduous is given but maple is not
between Red oaks and white oaks..... Red Oaks is given but White oaks is not given in the option
between Japenese maples and total maples....... Japenese maples is given but total maples is not given in the option

However, deciduous is related to maples, which is further related to japenese maples.
D:M = 8:1 and J:M = 1:5
D:M = 8:1 = 40:5 and J:M = 1:5. Hence D:M:J = 40:5:1 or D:J = 40:1
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An inventory of a neighborhood's trees found that 32 percent were Updated on: 15 Sep 2026, 06:19
Originally posted by kaustubhkohli12 on 15 Sep 2026, 06:12.
Last edited by Bunuel on 15 Sep 2026, 06:19, edited 1 time in total.
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KarishmaB

Why it can't be Conifers and Deciduous. First statement says 32% were confiners and rest 68% (most of it ), would be 34% . So that ratio would be less than 1 .
KarishmaB

Make a tree diagram of the trees to understand the relations.
To know the relation between the number of two types of trees, either both should be exact numbers available to us such as Spruces and Pines or their number should be in terms of the same variable such as Red Oaks (65% of Oaks) and White Oaks (25% of Oaks).

Of the given options, number of cedars is unknown so ignore. Ignore Coniferous and Deciduous for the time being because they will likely be the denominator in the ratio (since ratio is less than 1). Let's look for the smaller numerator first.

Japanese maples are 20% of 1/8th of Deciduous.

\(Japanese = \frac{1}{40} * Deciduous\)

\(\frac{Japanese}{Deciduous} = \frac{1}{40}\) ANSWER

This ratio we have.

­
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An inventory of a neighborhood's trees found that 32 percent were 16 Sep 2026, 01:54
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KarishmaB

Why it can't be Conifers and Deciduous. First statement says 32% were confiners and rest 68% (most of it ), would be 34% . So that ratio would be less than 1 .

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Question stem:
Select for A and for B two types of trees such that the ratio of the number of trees of the type selected for A to the number of trees of the type selected for B can be determined and is less than 1.

We should be able to determine the ratio. Deciduous trees can be anywhere from about 34% to something less than 68% of all trees. We know conifers are 32% of all trees so that is fine. But then, what is the ratio of conifers : deciduous? We cannot determine exactly because we do not know the exact percentage of deciduous trees. We have only a range. "Most of the rest" i.e. most of the 68% could be 35% or 40% or 50% etc.
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An inventory of a neighborhood's trees found that 32 percent were 17 Sep 2026, 19:52
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Hi kaustubhkohli12,

You've nailed one half of the requirement, so let's build from there.

The prompt actually has two conditions, and a valid pair must clear both:
1. The ratio A/B must be less than 1, and
2. The ratio must be determinable - a single exact number.

Your reasoning handles condition 1 perfectly: conifers are 32%, deciduous is more than the conifers, so Conifers/Deciduous is indeed less than 1. That part is correct.

Where it slips is condition 2. The passage says "most of the rest were deciduous" - not "all of the rest." So deciduous is not exactly 68%. It's only "most" of the 68% non-conifer trees, which could be anywhere from just over 34% up to almost 68%. Because that denominator floats, the ratio Conifers/Deciduous could be 32/40, or 32/50, or 32/60 - you can never pin it to one value.

So the pair fails: it satisfies "less than 1" but not "can be determined."

Contrast that with the winning pair. Japanese maples = 20% of maples = 20% of (1/8 of deciduous) = 1/40 of deciduous. Notice both quantities are expressed in terms of the same deciduous group, so the vagueness cancels out - the ratio locks to exactly 1/40, no matter what deciduous actually is.

The one-word test

Here's a quick way to feel the gap. Reread the sentence as if it said:

"32 percent were conifers and all of the rest were deciduous."

With "all," deciduous would be exactly 68%, and Conifers/Deciduous = 32/68 - now determinable, and your pair would work! But the real word is "most," and that single word is what makes the denominator unknown.

Whenever you see "most" or "some" attached to a group, treat that group's exact size as unknown - you can't use it as a fixed number in a ratio.

Answer: Column 1 (A) = Japanese maples; Column 2 (B) = Deciduous trees

kaustubhkohli12
KarishmaB

Why it can't be Conifers and Deciduous. First statement says 32% were confiners and rest 68% (most of it ), would be 34% . So that ratio would be less than 1 .

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