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At a given time, what was the ratio of the number of sailboats to the

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At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 20 Dec 2015, 06:21
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At a given time, what was the ratio of the number of sailboats to the number of motorboats on Lake X?

(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30.

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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 20 Dec 2015, 07:06
1
Let the number of sailboats =s
number of motorboats = m
(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
1.25m = 1.1s
=>(5/4) m = (11/10)s
=> s/m = 50/44 = 25/22
Sufficient

(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30
s-m = 30 or m-s = 30
Not sufficient

Answer A
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 23 Dec 2015, 00:27
Skywalker, I can understand the logic you used, but aren't we not allowed to equate sailboats and motorboats to each other?

If s was the initial no^ of sailboats and m was the initial number of motorboats, then, in the original equation, there is no relation given between then^

so, if we assume s#=5/4 s and m#=11/10 m, then #m#s#/m#= (5/4) s / (11/10) m => s# / m# =25s/22m => s/m = 22s#/25m# or 22/25 s#/m#[/m]
and in this case, the value of s/m will depend on s#/m# and hence statement I shouldn't be sufficient.

Is this assumption wrong?
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 23 Dec 2015, 01:32
appsy01 wrote:
Skywalker, I can understand the logic you used, but aren't we not allowed to equate sailboats and motorboats to each other?

If s was the initial no^ of sailboats and m was the initial number of motorboats, then, in the original equation, there is no relation given between then^

so, if we assume s#=5/4 s and m#=11/10 m, then #m#s#/m#= (5/4) s / (11/10) m => s# / m# =25s/22m => s/m = 22s#/25m# or 22/25 s#/m#[/m]
and in this case, the value of s/m will depend on s#/m# and hence statement I shouldn't be sufficient.

Is this assumption wrong?


hi,
you are correct prior to the coloured portion..
why are you taking ratio of s# and m#.... its not correct
what we require to do is equate both of them due to the statement
If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X...
so here s#=m#..
or (5/4) s =(11/10) m .... get s and m on one side and you will have s/m and other side you will have the ratio
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 23 Dec 2015, 09:55
chetan2u wrote:
appsy01 wrote:
Skywalker, I can understand the logic you used, but aren't we not allowed to equate sailboats and motorboats to each other?

If s was the initial no^ of sailboats and m was the initial number of motorboats, then, in the original equation, there is no relation given between then^

so, if we assume s#=5/4 s and m#=11/10 m, then #m#s#/m#= (5/4) s / (11/10) m => s# / m# =25s/22m => s/m = 22s#/25m# or 22/25 s#/m#[/m]
and in this case, the value of s/m will depend on s#/m# and hence statement I shouldn't be sufficient.

Is this assumption wrong?


hi,
you are correct prior to the coloured portion..
why are you taking ratio of s# and m#.... its not correct
what we require to do is equate both of them due to the statement
If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X...
so here s#=m#..
or (5/4) s =(11/10) m .... get s and m on one side and you will have s/m and other side you will have the ratio


Ah! did not register the "would have been" clearly!

Thanks a lot for the clarification chetan
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 23 Dec 2015, 10:35
(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
S=110/110(M+M/4)
S/M=8/11 ....Suff
(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30.
...M-S=30 ....Insuff

Ans: A
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 23 Dec 2015, 19:02
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

At a given time, what was the ratio of the number of sailboats to the number of motorboats on Lake X?

(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30.

In the original condition and the question, consider the number of sailboats as ‘s’ and the number of motorboats as ‘m’. Then, you can come up with a question ‘s:m=?.’ However, when a ratio is asked in a question, it is likely that con is the ratio, which is an answer. So, in 1) s=1.1(1.25m), since s:m is unique, it is sufficient. In 2) |s-m|=30, since s:m is not unique, it is not sufficient. Therefore, the answer is A.
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 01 Mar 2016, 04:50
we need to find s/m

St.1 increasing m 1.25 times means that s/m ratio became 1.25 times less than original. So, original ratio was 1.25*1.1=1.375. SUFF

St.2 INSUFF.

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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 01 Mar 2016, 17:46
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chetan2u wrote:
appsy01 wrote:
Skywalker, I can understand the logic you used, but aren't we not allowed to equate sailboats and motorboats to each other?

If s was the initial no^ of sailboats and m was the initial number of motorboats, then, in the original equation, there is no relation given between then^

so, if we assume s#=5/4 s and m#=11/10 m, then #m#s#/m#= (5/4) s / (11/10) m => s# / m# =25s/22m => s/m = 22s#/25m# or 22/25 s#/m#[/m]
and in this case, the value of s/m will depend on s#/m# and hence statement I shouldn't be sufficient.

Is this assumption wrong?


hi,
you are correct prior to the coloured portion..
why are you taking ratio of s# and m#.... its not correct
what we require to do is equate both of them due to the statement
If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X...
so here s#=m#..
or (5/4) s =(11/10) m .... get s and m on one side and you will have s/m and other side you will have the ratio


hi chetan2u

I don't understand your explanation.

I deduced x=1.1*1.25*y
(since it says if Y is 25%increased, X is 110% of y - Doesn't that mean 1.1*1.25*Y?)
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 01 Mar 2016, 17:59
rachitshah wrote:
chetan2u wrote:
appsy01 wrote:
Skywalker, I can understand the logic you used, but aren't we not allowed to equate sailboats and motorboats to each other?

If s was the initial no^ of sailboats and m was the initial number of motorboats, then, in the original equation, there is no relation given between then^

so, if we assume s#=5/4 s and m#=11/10 m, then #m#s#/m#= (5/4) s / (11/10) m => s# / m# =25s/22m => s/m = 22s#/25m# or 22/25 s#/m#[/m]
and in this case, the value of s/m will depend on s#/m# and hence statement I shouldn't be sufficient.

Is this assumption wrong?


hi,
you are correct prior to the coloured portion..
why are you taking ratio of s# and m#.... its not correct
what we require to do is equate both of them due to the statement
If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X...
so here s#=m#..
or (5/4) s =(11/10) m .... get s and m on one side and you will have s/m and other side you will have the ratio


hi chetan2u

I don't understand your explanation.

I deduced x=1.1*1.25*y
(since it says if Y is 25%increased, X is 110% of y - Doesn't that mean 1.1*1.25*Y?)


You are correct rachitshah. As per the given verbiage of statement 1, the equation if you have to set up will be s=1.1*1.25*m and not 1.25s = 1.1 m .

But the main point to note here is that this statement is sufficient to calculate the ratio of s/m at any given time.

Hope this helps.
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 12 Aug 2017, 09:00
Bunuel wrote:
At a given time, what was the ratio of the number of sailboats to the number of motorboats on Lake X?

(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30.


Can someone please give a detailed explanation to this problem. why 1.25m=1.1s?

The statement says "the number of sailboats on Lake X would have been 110% of the number of motorboats"

Doesnt it mean s=1.1m?
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Re: At a given time, what was the ratio of the number of sailboats to the  [#permalink]

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New post 13 Aug 2017, 05:01
tejasridarsi wrote:
Bunuel wrote:
At a given time, what was the ratio of the number of sailboats to the number of motorboats on Lake X?

(1) If the number of motorboats on Lake X had been 25% greater, the number of sailboats on Lake X would have been 110% of the number of motorboats on Lake X.
(2) The positive difference between the number of motorboats on Lake X and the number of sailboats on Lake X was 30.


Can someone please give a detailed explanation to this problem. why 1.25m=1.1s?

The statement says "the number of sailboats on Lake X would have been 110% of the number of motorboats"

Doesnt it mean s=1.1m?


You are only quoting a part of the first statement and ignoring the red part above. This is where 1.25s will come from.
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Re: At a given time, what was the ratio of the number of sailboats to the   [#permalink] 13 Aug 2017, 05:01
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