In the figure above, what is the length of AD?

Question

https://gmatclub.com/forum/download/file.php?id=25103 In the figure above, what is the length of AD? (1) AC = 6 (2) BD = 6 2014-12-22_1955.png

uday1409 · Answer

1. CD is not known.Insufficient
2.AB is not known. Insufficeint

1+2 > > AB+2(BC)+CD=12 >> AD+BC=12
BC is not known. Insufficient

E

beattheheat · Answer

Determine the length of AD?

Statement 1: AC = 6
We don't know CD -- Insufficient

Statement 2: BD = 6
We don't know AB -- Insufficient

Combining 1&2:
AC + BD = 12, here BC is accounted twice and since we don't know BC -- Insufficient

Answer E

qw1981 · Answer

First thing you need to understand after looking at the figure position of points related to each other is not given. DO NOT ASSUME.

S(1): Tells nothing about CD hence N.S
S(2): Tells nothing about AB hence N.S

Event after combining we do not know distance between B & C which could be 6 or 0.01 . Hence Not sufficient.

I think this could have been a little more trickier if we were asked maximum length of AD will always be smaller then which number. The answer would be 12 assuming B&C are very close to each other and even if they are on top of each other the maximum length can be 12.

g106 · Answer

AD = AB+BC+CD

From Statement 1: AC =6; AD = 6+CD(We cannot find using given information)
Statement 2: BD = 6; AD= 6+AB (Again, We cannot find using given information)
Combining both also not sufficient to find the value

Ans : E

robinpallickal · Answer

Hi Bunnuel,

My soln was:

AD = AC + BD - BC (as in AC + BD , BC is already counted)
NOw as AC=BD = 6, both points B and C are same. ( Taking St 1 and St 2 together)

so AD = 12.

Can you Pls. guide me where I went wrong?

Bunuel · Answer

https://gmatclub.com/forum/download/file.php?id=25103 
The red part is not correct. Consider AB = 5, BC = 1, and CD = 5 OR AB = 4, BC = 2, and CD = 4.

GMATBusters · Answer

Try to draw the line diagram in mind to solve the question in seconds.
As we do not know the overlap of AC & BD, it is insufficient.

See the sketch.

amanvermagmat · Answer

We can also solve this question by taking AB=x, BC=y, CD=z. So we need to find AD, which is x+y+z

Statement 1:
Gives us x+y = 6, so it is not sufficient.

Statement 2:
Gives us y+z = 6, so again not sufficient.

Combining, we can add the two, we get:
x+y + y+z = 6+6 OR x+y+z + y = 12
Unless we know y, we cannot find x+y+z. So not sufficient.

Hence  E answer

dcummins · Answer

If we were told that A,B,C and D were equidistant then AD would equal 9.

But we aren't, so we cannot deduce that each distance is equal.

CD could equal 5 and BC could equal 1, so AD= 11 in this case.

Combined insufficient.

CEdward · Answer

We can jump straight to a combination of both.

Evidently, there is an overlap between the two regions, but we don't know how much overlap there is.

E.

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In the figure above, what is the length of AD?

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