The beach ball we played with has a density of 10 grams per cubic centimeter

does not make sense.

The statement " the beach ball we played with has a density of 10 grams per cubic centimeter" does not make sense.

 Reasoning.

Inflated beach balls have a very low density, they are pretty much only air, plus the weight of the ball per se. Certainly that density is much lower than the density of water.

Inflated beach balls fall slowly in the air because their density is very close to the density of air and float on water because their density is less than the density of water.

Being the density of pure water 1 g/cm^3 you can predict, without any calculation, that the density of the beach ball is less than that and never 10 g/cm^3 which is 10 times the density of pure water.

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.