Final answer:
To determine how many weeks it takes for the number of locusts to triple, we solve the equation 3 • 400 = 400 • (1.1)^t for ‘т’ to find that it takes approximately 11.53 days, which is about 1.65 weeks.
Step-by-step explanation:
The question asks how many weeks it takes for the number of locusts to triple according to the exponential growth function N(t) = 400 • (1.1)^t, where N represents the number of locusts after t days. To find when the population triples, we must solve the equation 3 • 400 = 400 • (1.1)^t. Dividing both sides by 400 gives us 3 = (1.1)^t, and we can now use logarithms to solve for t. After calculating, we convert the days into weeks by dividing by 7.
Let's solve step-by-step:
- 3 = (1.1)^t
- t = log(1.1)³
- t ≈ 11.53 days (after rounding to two decimal places)
- Weeks = 11.53 / 7 ≈ 1.65 weeks
Thus, the number of locusts is tripled every 1.65 weeks.