Joviest wrote:

(1) n*n*n(1-x*x) < 0

Here (1-x^2) can be greater than or less than 0

So cant say

(2) x*x-1 < 0

x^2 -1 < 0

x^2 < 1

Gives x >-1 or x<1 again cant say yes or no

Combine, we now know from 2 that 1-x^2 > 0

So that means x^2 <1 which means x>-1 and x<1

The answer is C.

2. What is the volume of a certain rectangular solid?

(1) Two adjacent faces of the solid have areas 15 and 24, respectively.

(2) Each of two opposite faces of the solid has area 40.

The answer is C.

Thanks:)[/code]

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Its a bit confusing the way you have written the powers ...

(1) n*n*n(1-x*x) < 0

Here (1-x^2) can be greater than or less than 0

So cant say

(2) x*x-1 < 0

x^2 -1 < 0

x^2 < 1

Gives x >-1 or x<1 again cant say yes or no..insufficient

Combine, we now know from 2 that 1-x^2 > 0

but that still doesnt give the answer

I think E

2. What is the volume of a certain rectangular solid?
(1) Two adjacent faces of the solid have areas 15 and 24, respectively.

you can take any set lb,bh,lh ..it will get you the same answer

b*h = 15

l*h = 24

not sufficient three unknowns ,two equations.

(2) Each of two opposite faces of the solid has area 40.

l*b = 40

Not sufficient

Combine , three unknowns, three equations, sufficient...C