Ambiguous problem - Princeton Review

[Incisive16]

I encountered this problem in a Princeton test.

a = b + 2

Col A : (a^2) - 2ab + (b^2)
Col B : 2a - 2b

SPOILER: C

Shouldn't the answer be D...the values of a and b are not given.

Do we have problems like these in actual GRE ?

[coyote]

Yes we do face similar problems in GRE.

Given a+b = 2
Thus a-b = 2

Column A : a^2-2ab+b^2 = (a-b)^2 = 2^2 = 4

Column B : 2a - 2b = 2(a-b) = 2*2 = 4

Thus ANSWER :C

It is not a very difficult problem. But the key here is factorization of column A.

Hope that helps.

[Incisive16]

Yes thats an easy one. I marked it D straight away since values of a and b were not given.

[coyote]

Here are some formulae which you may find useful for solving some problems.

[Serenity]

col a = x

col b = y

Given:

X > Y

What is the answer? Must it be D becuase no values are given?

[coyote]

Originally Posted by Serenity

col a = x
col b = y
Given:
X > Y
What is the answer? Must it be D becuase no values are given?

Serenity , the given information is not a>b but precisely a=b+2

Refer to my post above. The answer is C

[nitwit87]

i'll be yearning for these kind of probs on 15 nov

[coyote]

Originally Posted by nitwit87

i'll be yearning for these kind of probs on 15 nov

Ah. Good Luck nitwit!

(Btw, quite an interesting username )

[Serenity]

Originally Posted by coyote

Serenity , the given information is not a>b but precisely a=b+2

Refer to my post above. The answer is C

relax.

I made a new problem to illustate the point that variables have relationships even if their are not defined as numbers.

[coyote]

Originally Posted by Serenity

relax.

I made a new problem to illustate the point that variables have relationships even if their are not defined as numbers.

Oops! Apologies, Serenity.