Question

In an insect colony there are 270 insects after 9 days. If there were initially 80 insects how long will it take the population to grow to 800 insects?

Answer 1

Answer:

The time it will take the population to grow to 800 insects is 17 days.

Step-by-step explanation:

The growth function of the insects is exponential.

The exponential growth function is:

$y=a(1+r)^{t}$

Here,

y = final value

a = initial value

r = growth rate

t = time taken

It is provided that there were 270 insects after 9 days and initially there were 80 insects.

Compute the value of r as follows:

$y=a(1+r)^{t}\\\\270=80(1+r)^{9}\\\\3.375=(1+r)^{9}\\\\\ln(3.375)=9\cdot \ln(1+r)\\\\0.135155=\ln(1+r)\\\\1+r=1.14471\\\\r=0.145$

Now, compute the time it will take the population to grow to 800 insects as follows:

$800=80(1+0.145)^{t}\\\\10=(1.145)^{t}\\\\\ln(10)=t\cdot \ln(1.145)\\\\t=17.00522\\\\t\approx 17$

Thus, the time it will take the population to grow to 800 insects is 17 days.