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# URGENT help required, OG 13 questions

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Manager
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 10:37
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 10:41
rajrj17 wrote:
Q2) the price of lunch for 15 people was $207.00, including a 15% gratuity for service. What was the average price per person EXCLUDING the gratuity? a)11.73 b)12 c)13.8 d)14 e)15.87 Here the word EXCLUDING is used. So 0.15 * 207=$31.05
Therefore,207-31.05=$175.95 So the average cost per person=175.75/15=11.73 So ans should be (A) IMO. the stem before the question states that 207 INCLUDES 15% gratuity. hence 1.15x = 207 and bill (without gratuity) would have only been 180. add 15% gratuity and that arrives at the total bill for 207. now the question asked is to calculate amount per person EXCLUDING gratuity which is per person share of$180 bill that will be \$12 when shared equally between 15 people)
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 10:42
you guys are amazing!
thank you so much!
I've actually recently finished the whole of OG13 PS, so I just posted my questions.
Q1) D
Q2) B
Q3) B
Q4) D
Q5) D
Q6)E
Q7) D
Q8)D
Q9) B
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 22:26
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[quote="Zarrolou"]That's a lot of questions !

Q1)A ladder of a fire truck is elevated to an angle of 60 degrees and extended to a length of 70 feet. if the base of the ladder is 7 fet above the ground, how many feet above the ground does the ladder reach?

The ladder forms a 30 60 90, triangle which has dimentions 1x $$\sqrt{3}$$ 2, the hip is $$70=2x$$ so $$x=35$$, the H of the triangle is $$35\sqrt{3}$$, but the ladder is 7 feet from the ground => it reaches [m]7+35[squar

I dont understand how youve put hyp=2x. Hyp is opp the 90 deg angle, so shouldnt ishould we put it equal to under root three? I dont understand OGs explanation
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 22:37
Zarrolou wrote:
Q3) for any psitive integer n, the sum fo the first n positive integers equals [n(n+1)]/2. what si the sum of all the even integers betwen 99 and 301?

100 ... 200 ... 300
Between 200 and 100 there are 200/2-100/2+1=51 even integers
Between 300 and 200 there are 300/2-200/2+1=51 even integers
But we counted 200 twice, so tot even entegers = $$51+51-1=101.$$
As you can see their mean is 200
So tot sum is$$200*101=20200$$
IMO B

Why are you adding one both times for even integers?
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 22:45
usre123 wrote:
Zarrolou wrote:
Q3) for any psitive integer n, the sum fo the first n positive integers equals [n(n+1)]/2. what si the sum of all the even integers betwen 99 and 301?

100 ... 200 ... 300
Between 200 and 100 there are 200/2-100/2+1=51 even integers
Between 300 and 200 there are 300/2-200/2+1=51 even integers
But we counted 200 twice, so tot even entegers = $$51+51-1=101.$$
As you can see their mean is 200
So tot sum is$$200*101=20200$$
IMO B

Why are you adding one both times for even integers?

Its the formula. let me give you an example, between 4 and 8 there are 3 even numbers (4,6,8). If you don t add 1, you obtain 8/2=4 4/2=2 so 4-2=2 and not 3. Thats why you have to add one.
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 22:46
Could someone please do question 4.thanks
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Re: URGENT help required, OG 13 questions [#permalink]

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08 Apr 2013, 22:50
usre123 wrote:
Zarrolou wrote:
That's a lot of questions !

Q1)A ladder of a fire truck is elevated to an angle of 60 degrees and extended to a length of 70 feet. if the base of the ladder is 7 fet above the ground, how many feet above the ground does the ladder reach?

I dont understand how youve put hyp=2x. Hyp is opp the 90 deg angle, so shouldnt ishould we put it equal to under root three? I dont understand OGs explanation

The proportions in a 30 60 90 are 1x:$$x\sqrt{3}$$:2x. The text says that "it extends for 70 feet", and this side is opposite to the right angle and therefore the longest one and therefore ( because $$2>\sqrt{3}$$) equals 2x. Now that you have x, you can obtain all the sides.
Hope it s clear now
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Re: URGENT help required, OG 13 questions [#permalink]

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09 Apr 2013, 02:28
usre123 wrote:

Q1)A ladder of a fire truck is elevated to an angle of 60 degrees and extended to a length of 70 feet. if the base of the ladder is 7 fet above the ground, how many feet above the ground does the ladder reach?
a) 35
b) 42
c) 35 \sqrt{3}
d) 7+ 35\sqrt{3}
e) 7+42\sqrt{3}
...

You violated almost all the rules we have on the forum: rules-for-posting-please-read-this-before-posting-133935.html Topic locked!

All, question have been discussed before.
#2: the-price-of-lunch-for-15-people-was-207-00-including-a-131794.html
#3: for-any-positive-integer-n-the-sum-of-the-first-n-positive-127817.html
#4: last-year-the-price-per-share-of-stock-x-increased-by-k-89307.html
#5: of-the-300-subjects-who-participated-in-an-experiment-using-134147.html
#6: if-m-0-and-x-is-m-percent-of-y-then-in-terms-of-m-y-is-103387.html
#7: seven-pieces-of-rope-have-an-average-arithmetic-mean-lengt-144452.html
#8: topic-144735.html
#9: list-t-consist-of-30-positive-decimals-none-of-which-is-an-131755.html

All OG13 questions with solutions are here: the-official-guide-quantitative-question-directory-143450.html
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Re: URGENT help required, OG 13 questions   [#permalink] 09 Apr 2013, 02:28

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