What is the minimum area of cardboard required to make a rectangular b

Hi,

This is a very good question for a C-Trap answer in GMAT DS questions.

Here the key is to find the area of the rectangular box with no top,

i.e., if l is the length, b is the breadth and h is the height, then the area of five faces(with no top)

l*b + 2 b *h *+ 2 * h*l

So here the key is we need to know, b*h, l*b and h*l

Technically we need to length, breadth and height values.

Statement I is insufficient:

We know only the base area, nothing about the height or the length and the breadth values separately.

Statement II is insufficient:

We know the volume,

i.e.,

L*B*H = 23 cubic feet,

Again, we can’t really find the individual lengths,

Together still it is insufficient:

Here is where, student might end up choosing a trap answer that both together it is sufficient.

From statement I, we know l *b = 23

From Statement II, we know l*b*h = 23

So h = 1,

But still we don’t know, what is length and breadth individually, then we can’t figure that the area (b*h and h*l).

So together still it is insufficient.

Answer has to be E.

Hope this helps.