Data Sufficiency

Is a=b?
1) a^2=b^2
2) a=1

*An answer will be posted in 2 days

Max@Math Revolution wrote:Is a=b?
1) a^2=b^2
2) a=1

*An answer will be posted in 2 days

(1) NOT SUFFICIENT. A could equal B, or A could equal -B.
(2) NOT SUFFICIENT. B could be any value.

Combined (1) & (2). NOT SUFFICIENT. A = 1, B could equal 1 or -1.

1) a^2=b^2 is NOT SUFFICIENT, plausible set of numbers that satisfy this condition is {-1,1,-2,2,-3,3....so on}

2) a=1, gives no info. whatsoever on the value of b so, NOT SUFFICIENT

COMBINING BOTH OPTIONS, if a=1 , b^2=1 --> b= +/-1 plausible set is {-1,1} of {NO,YES} so NOT SUFFICIENT

So, the answer is E

There are 2 variables in the original condition. Hence, we need 2 equations, and there is a high chance that C is the correct answer. Using 1) & 2), from a=1 and b=-1, 1, the answer is both yes and no. The conditions are not sufficient and the correct answer is E.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.