Question

A swim team is divided into age groups: Guppies, stingrays, and sharks. There are 20 swimmers in the Stingray group. If we randomly select 10 swimmers and 4 are Stingrays. How many swimmers can we estimate are on the team? Finish a We can estimate that there are swimmers on the team,​

Answer 1

If you choose 10 swimmers and 4 are Stingrays, you can say that Stingrays make up roughly 40% of the swimmers. If 20 Stingrays make up 40% of all the swimmers, we just have to find what number 20 is 40% of. That’s easy enough by cross multiplication:

20/x = 40/100

20/x = 4/10

20/x = 2/5

x = 50.

Double check by multiplying 50 * 0.4. Since 50 * 0.4 = 20, we know we have the right answer. There are about 50 swimmers on this team.