Therefore, volume of iron in the tank

= 20 cubic feet - 332791116 cubic inches

= 1280516 cubic inches.

But 1 cubic foot of iron weighs as much as 7.8 cubic feet of water, i. e., 7.8 × 1000 ounces, or 7800 ounces.

∴ Weight of tank = 1280516 × 78001728 × 16 pounds.

∴ Weight of tank = 361.199 pounds, Ans.

Example: A wood pile is 8 feet high and 40 feet long. The sticks are 4 feet long. How many cords in it?

Solution: Being 8 feet high, it is 2 cords high. 40 feet in length equal 5 cords in length. Hence, the pile contains 2 × 5 cords, or 10 cords.

To estimate a bin: