Question

Biologists were studying the interesting exponential growth of barn owls on a Pacific Island. In 2000, through sampling,

they found that the population of barn owls on the island was 300. When they tested for the second time in 2004, they
estimated that there were 643 owls. If x represents number of years after 2000, which equation models the population
of barn owls?
y = 643(1.21)
Oy=643(1.42)
y=300(1.21)
y = 300(1.42)

Answer 1

y = 300(1.21)ˣ

Explanation:

• Initial number = 300
• Number after 4 years = 643

Since it is exponential growth, and x=4, we get the value of growth per year:

• 643 = 300*x⁴
• x=
  `\sqrt[4]{643/300}` = 1.21

So the function is:

• y = 300(1.21)ˣ