Question

One cubic meter of water weighs approximately 2200 pounds. There are 100 cm in one meter. If you have a box-shaped fish tank that measures 30 cm by 30 by 80 cm, what is the weight of the water that can be held in the tank?

Answer 1

158.4 pounds

Explanation:

first find the volume of the tank

`V = 30 * 30 * 80`

`V = 72000 cm^3`

to convert this to m^3 we know that 1m = 100cm

`V = 72000 cm^3 * \left(\frac{1\,\text{m}}{100\,\text{cm}}\right)^3`

`V = 72000 cm^3 * \left(\frac{1\,\text{m}^3}{100^3\,\text{cm}^3}\right)`

the cm^3 cancel out.

`V = (72000)/(100^3) m^3`

`V = 0.072\,m^3`

by simply converting the side-lengths to meters beforehand can give you this answer directly:

`V = 0.3 * 0.3 * 0.8 = 0.072 m^3`

it is given that 1 meter cube of water weighs about 2200 pounds.

`1\,m^3 = 2200 \,\text{lb}`

multiply both sides with 0.072 to find our answer:

`1\,m^3 * 0.072 = 2200 * 0.072 \,\text{lb}`

`0.072\,m^3 = 158.4 \,\text{lb}`

hence the weight of the water in the tank would be 158.4 pounds!