What is the volume of water in an inverted square pyramid with given dimensions?

[macmac410]

Homework Statement

An inverted square pyramid has a height equal to 8m and a top edge equal to 3m. Initially, it contains water to a depth of 5m. What is the initial volume of water in the tank?

Homework Equations

volume=1/3bh

where b is e2, as area of square base.

The Attempt at a Solution

the height is given and the sides of square so can easily compute for the volume of the entire pyramid which is
vp(volume of pyramid)=24
the problem is i don't know the next step to get the volume of the liquid.
I tried so many formulas but theses none of those would fit in. HELP!

 

[Rayquesto]

8 times 3 times 1/3 is 24
24/height= changebase or something like that
24m^3/5m=4.8meters-3meters=base=1.8meters is new base when its 5 full
bh1/3=volume
1.8 times 5 times 1/3 is 3meters^3
3 meters cubed should be your answer.
is it? I am no expert though

 

[macmac410]

I think it is not.
man, I'm really confused..
But anyway thanks for the help.
I need the volume of the water in the pyramid.

 

[Rayquesto]

well the maximum volume contained in the pyramid is 8 meter cubed. so, 1.8 meters being the top baes where 5 meters is the height and where the volume is 3 meters cubed when the water is filled 5 meters high makes perfect sense to me.

 

[macmac410]

No, the maximum volume of the pyramid is 24m^3
since
volume of pyramid is 1/3 bh
where b is the area of bAse..

 

[Rayquesto]

b=8
h=3
1/3=constant
8 times 3 times 1/3 is 8 meters cubed