Find the weight of a "tank" with salt water

A tank, open at the top, is made of sheet iron 1 in. thick. The internal dimensions of the tank are 4 ft. 8 in. long; 3 ft. 6 in. wide; 4 ft. 4 in. deep. Find the weight of the tank when empty, and find the weight when full of salt water. (Salt water weighs 64 lb. per cu. ft., and iron is 7.2 times as heavy as salt water.)

Note:
1 in = 0.0833 ft.
4 ft. 8 in. = 4.6667 ft.
3 ft. 6 in. = 3.5 ft.
4 ft. 4 in. = 4.3333 ft.

The answers on the book were 3,453.9 lbs and 7893.6 lbs.

I can't get any answer close to the answer on the book.
And most of all, i can't illustrate the tank clearly.
Water tanks should be cylindrical right?

What I did was this:

http://i53.tinypic.com/29pb7tt.jpg

Thanks for the help guys.

The size of the bottom (including the parts under the walls), in feet, is 4 5/6 x 3 2/3 x 1/12.

The size of the two long walls (not including the bottom but including 1 inch at the sides) is 4 5/6 x 4 1/3 x 1/12.

The size of the two short walls (not including the bottom or 1 inch at the sides) is 3 1/2 x 4 1/3 x 1/12.

I multiplied the last two volumes by 2, added the first volume, multiplied by 64 and 7.2 and got 3,453.9.

Quote:

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Originally Posted by emakarov

The size of the bottom (including the parts under the walls), in feet, is 4 5/6 x 3 2/3 x 1/12.

The size of the two long walls (not including the bottom but including 1 inch at the sides) is 4 5/6 x 4 1/3 x 1/12.

The size of the two short walls (not including the bottom or 1 inch at the sides) is 3 1/2 x 4 1/3 x 1/12.

I multiplied the last two volumes by 2, added the first volume, multiplied by 64 and 7.2 and got 3,453.9.

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Thank you very much!!!! so the volume of water will be (4 1/3 x 3 1/2 x 4 2/3) x 64 = 4,529.777778 + 3453.9 = 7983.67
:)