Question

A swimming pool measures 48.6 meters by 26.4 meters. how many grams of water are needed to fill the pool, whose average depth is 7.5 feet? assume the density of water to be 1.0 g/ml. use significant figures. use "e" for scientific notation. do not enter "grams" as part of your answer.

Answer 1

1 ft = 30.48 cm

so

7.5 feet is 7.5×30.48 cm = 228.6 cm

Then the volume of the pool is

... V = LWH = (4860 cm)(2640 cm)(228.6 cm) = 4.86×2.64×0.2286×10³⁺³⁺³ cm³

... = 2.9×10⁹ cm³ . . . . . rounded to 2 significant figures to match 7.5

The mass of water is

... (2.9×10⁹ cm³) × (1 g/cm³) = 2.9×10⁹ g

In the desired form, the number of grams is 2.9e9.