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!

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

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

Could you pls post the explanation provided in the MGMAT.

Thanks

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.