Question

Researchers count 30 tagged zebras and 150 total zebras in an area of a game reserve. if researchers had previously tagged 80 total zebras at the game reserve, about how many total zebras live at the game reserve? write a proportion to extimate the total population.

Answer 1

About 400 zebras live at the game reserve.

The proportion would be 
30/150 = 80/x

This is because 30 zebras are tagged out of 150 in one area.  We know that they tagged 80 total zebras out of x total zebras.

To solve this, cross multiply:
x*30 = 150*80
30x = 12000

Divide both sides by 30:
30x/30 = 12000/30
x = 400