1 is suff
2 talks about wide and not height so not suff

Ans A

You need to know the width also. The stairs are not going to be stacked (3/4) foot high on top of each other the WIDTH must be know.........

pierce22884 wrote:You need to know the width also. The stairs are not going to be stacked (3/4) foot high on top of each other the WIDTH must be know.........

No you don't.

Whether the steps are 5 feet wide each or 1 inch wide, if we know the height of each step we know how many steps it takes to gain 9 feet of altitude.

As a complete aside, I think you have depth confused with width (although the depth of the steps is also irrelevant to answering the question posed).

Height of step = vertical distance;
width of step = side to side distance; and
depth of step = how far from the edge of one step does the next step begin.

pierce22884 wrote:If the two floors in a certain building are 9 feet apart, how many steps are there in a set of stairs that extends from the first floor to the second floor of the building?

1) Each step is (3/4) foot high.

2) Each step is is 1 foot wide.


[spoiler]OA: A[/spoiler]

Please help me understand as to why.

two floors are 9 feet apart..
St.1 Each step is (3/4) foot high. so no, of steps = 9/(3/4) = 12 =========suff.
St.2 Each step is is 1 foot wide.
width of stair don't solve the problem.... as we want height ....=========insuff.

Ans. A