Got a doubt in another DS Question:

Q. Is the population of country C in year 2002 greater than that in year 2000?
I. The population of country C decreases and increases by same % in alternate years.
II. The population of country C in year 2001 was greater than that in year 2000.

Answer given was (4): Both cannot answer the question.
How?

hi
usually in complex algebra, the square root of -1 is almost always taken as i alone. the sign is usually ignored. but in CAT, i guess it wud depend on the question setters. u will probably have to take a call on what u want to choose.... personally, i wud go for just i alone without the sign....on the other hand, the safer option wud be to just leave the question if u don't want to take the risk... there r so many other unambigous quesions left...
rgds,
rakesh

When you use both the equations you get x^2 + 1 = 0.
Thus x^2 = -1. Which means x = root (-1) = i.

Correct me if I am wrong.

which came first ...the egg or the hen ?

x^2 + 1 = 0
X^2 = -1
x = +- i

what is the value of x now ??


Ps:- We can "solve" the equation ...but we cannot "determine" the value of x .....i hope i havent confused u

oops... my mistake.. thought we wud get x squared equal to 1 .. that is y i said it cudn't b uniquely determined...
sorry again,
rgards,
rakesh

When you use both the equations you get x^2 + 1 = 0.
Thus x^2 = -1. Which means x = root (-1) = i.

Correct me if I am wrong.

Hi,
I also marked the option which says that it can not be answered even with the help of both options.
But i have seen at two places in IMS section tests where they they say you can find the value of x.
For instance in DI sectional tests of IMS - Test 3 of PART-C
They have marked the option that you can find the answer. I got my answer wrong in two successive sectional tests in IMS.
Thats why i got really doubtful of this. In TIME they always suggest,mark the option that u can't find the answer. I don't know how come these institutes are suggesting different approaches.

Bye,
Amit

yes, the answer is D. plz note that if u CANNOT find a unique solution for the variable to be dtermined in DS questions, it is always D. i know it is a repeat post, but this is very important...:-)so junta, plz 4give this bugger with nthg much to do but browse....;-)
rgds,
rakesh

what is the value of x means ONE single value ....
So i would mark "D" as the answer (i.e cannot determine value of x even after using the two statements)