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In the figure above, all angles are right angles. If the lengths a, b

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In the figure above, all angles are right angles. If the lengths a, b [#permalink]

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In the figure above, all angles are right angles. If the lengths a, b, u, and v are integers, what is the perimeter of the six-sided figure?

(1) ab = 77

(2) u/v = 3/5

[Reveal] Spoiler:
Attachment:
2957-1.gif
2957-1.gif [ 843 Bytes | Viewed 3729 times ]
[Reveal] Spoiler: OA

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Re: In the figure above, all angles are right angles. If the lengths a, b [#permalink]

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Line segment u and v can be moved to form a rectangle.
Perimeter of a rectangle = 2(l + w)

St1: ab = 77
11 * 7 = 77 --> Perimeter = 2(11 + 7) = 36
77 * 1 = 77 --> Perimeter = 2(77 + 1) = 156 --> This case can be ruled out because u and v are integers.
Sufficient.

St2: u/v = 3/5 --> 0.6v. Since u and v are integers, u can assume a minimum value of 3 and v can assume a minimum value of 5.
a = u + some value = 3 + some value
b = v + some value = 5 + some value
Perimeter cannot be calculated.
Not Sufficient.

Answer: A
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Re: In the figure above, all angles are right angles. If the lengths a, b [#permalink]

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New post 01 Apr 2016, 03:49
Statement 1

Firstly until and unless all angles are right angles, it doesn't matter the value of u & v, By the same amount of perimeter deduced from the piece due to u-v occupation - it adds that pieces by the same

So essentially the perimeter of the area will remain = 2 (a+b)
as area is 77 = a * b (as given a and b can be integer)
so two case a= 11,b=7 or a =7, b=11

Therefore the perimeter in both case 2(11+7) & 2(7+11) is the same, i.e. 36

Statement 2

Here you know Ration of u/v, it is not sufficient as we don't know the factor in comma, it's the ration of primes with no factor involved

Plus knowing u & v can't tell you about the perimeter 2 (a+b)

Hence Option A
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Re: In the figure above, all angles are right angles. If the lengths a, b [#permalink]

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New post 03 Apr 2016, 03:13
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.

In the figure above, all angles are right angles. If the lengths a, b, u, and v are integers, what is the perimeter of the six-sided figure?

(1) ab = 77

(2) u/v = 3/5


When you modify the original condition and the question, the length of the perimeter is 2(a+b). That is, you only need to figure out a+b. a and b are integers and (a,b)=(7,11),(11,7) from 1) ab=77. Also, a+b=18 is always derived and sufficient, which makes A the answer.
The reason (a,b)=(1,77) is not valid is if a=1, you cannot subtract u, which makes 1 impossible.
Thus, A is the answer.


 Once we modify the original condition and the question according to the variable approach method 1, we can solve approximately 30% of DS questions.
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Re: In the figure above, all angles are right angles. If the lengths a, b [#permalink]

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New post 17 Sep 2017, 03:29
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Re: In the figure above, all angles are right angles. If the lengths a, b   [#permalink] 17 Sep 2017, 03:29
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