overlapping ranges DS question

[Guest]

Is x > 5 ?

1. x^2 > 25
2. 2x + 7 > 0

Is the answer C ?

Here is how i worked it out

1. x > 5 or x < -5
so, insufficient
2. 2x > -7
=> x > -3.5
so, insufficient

Combining the two x > 5. Hence, C.

[H_to_750]

The answer is C

In statment two we know that X is greater than - 3.5
Statment one tells is X = 5 or X = -5

When we combine we know that x is 5

So it answer the questions if X > 5 and the answer is NO it is not greater than 5 it is 5

[RonPurewal]

The answer is C

In statment two we know that X is greater than - 3.5
Statment one tells is X = 5 or X = -5

When we combine we know that x is 5

So it answer the questions if X > 5 and the answer is NO it is not greater than 5 it is 5

whoa, no.

statement (1) is an inequality. it certainly won't magically resolve itself into an equality!

as the first poster correctly observes, x^2 > 25 means that either x > 5 or x < -5. think about it conceptually: x^2 doesn't care whether x is positive or negative (because the square is always positive, no matter what). therefore, as long as the 'size' of x (regardless of sign) is at least 5, x works; hence the 2 different inequalities.

in conjunction with statement (2), the possibility that x < -5 is ruled out, so we have x > 5.