MGMAT DS

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gmatnmein2010: Master | Next Rank: 500 Posts; Posts: 185; Joined: Thu Feb 04, 2010 3:06 am; Thanked: 6 times

by gmatnmein2010 » Sun Feb 14, 2010 7:34 pm

Ten years ago, scientists predicted that the animal z would become extinct in t years. What is t?

(1) Animal z became extinct 4 years ago.

(2) If the scientists had extended their extinction prediction for animal z by 3 years, their prediction would have been incorrect by 2 years.

this was from MGMAT tests and i opted for A; which is wrong

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Source: Beat The GMAT — Data Sufficiency | Sun Feb 14, 2010 7:34 pm

fibbonnaci: MBA Student; Posts: 403; Joined: Tue Dec 22, 2009 7:32 pmFollowed by: 22 members; Thanked: 98 times

by fibbonnaci » Sun Feb 14, 2010 10:24 pm

woww this is a DS and CR mixed question.

from 1) we can get that the animal became extinct 6 years after the scientists made prediction. but what was t according to the scientists is not known. they could have told the animal will be extinct in 4 years and the animal actually became extinct after 6 years. Insufficient.

2) we just have the information that when we add 3 to t it differs from the correct value by 2 years. But is it 2 years greater or lesser than the correct value. we still cannot find t. Insufficient.

combining 1 and 2, we know the hard facts but still do not know the hypothesized years of the scientists.
They could have predicted 5 years the animal will go extinct. adding 3 -> it is 2 years greater than the the correct value.
or they could have predicted the animal will go extint in 1 year. adding 3-> it is 2 years less than the correct value.
so you see we have two values for t. t=1 or 5. Insufficient.

thus both the statements are not sufficient to answer the question. E

Hope this helps!

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gmatmachoman: Legendary Member; Posts: 2326; Joined: Mon Jul 28, 2008 3:54 amFollowed by: 2 members; Thanked: 173 times; GMAT Score:710

by gmatmachoman » Sun Feb 14, 2010 11:59 pm

Ya indeed..This is a classical DS..I liked it very much!! Even while having my lunch, it kept me occupied...

R&D on GMAT algorithm:

https://www.beatthegmat.com/r-d-on-gmat- ... tml#305739

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sumanr84: Legendary Member; Posts: 758; Joined: Sat Aug 29, 2009 9:32 pmFollowed by: 2 members; Location: Bangalore,India; Thanked: 67 times

by sumanr84 » Mon Feb 15, 2010 3:25 am

I never encountered this CR+DS Q while doing my MGMATs. Quite Interesting,

Could you pls post the explanation provided in the MGMAT.

Thanks

I am on a break !!

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komal: Legendary Member; Posts: 777; Joined: Fri Jan 01, 2010 4:02 amFollowed by: 47 members; Location: Mumbai, India; Thanked: 117 times

by komal » Mon Feb 15, 2010 6:31 pm

gmatnmein2010 wrote:Ten years ago, scientists predicted that the animal z would become extinct in t years. What is t?

(1) Animal z became extinct 4 years ago.

(2) If the scientists had extended their extinction prediction for animal z by 3 years, their prediction would have been incorrect by 2 years.

this was from MGMAT tests and i opted for A; which is wrong

(1) The only thing we can get from this statement is when animal z actually extincted: 4 years ago or 6 years after the prediction. Not sufficient.

(2) Also not sufficient: t+3=actual extinction +/- 2.

(1)+(2) Animals extincted 6 years after the prediction: t+3=6-2 --> t=1 OR t+3=6+2 --> t=5. Two answers, not sufficient.

Answer: E.

https://www.e-gmat.com/

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