Final answer:
To find the number of people who have heard the news when its rate of spread is 1 thousand people per day, we need to solve the equation y = f(t) = (10) / (1 + 150e^(-0.1t)) = 1.
Step-by-step explanation:
To find the number of people who have heard the news when its rate of spread is 1 thousand people per day, we need to solve the equation y = f(t) = (10) / (1 + 150e^(-0.1t)) = 1.
To solve this equation, we can start by multiplying both sides of the equation by (1 + 150e^(-0.1t)). This gives us 10 = 1 + 150e^(-0.1t).
Next, we can subtract 1 from both sides of the equation to isolate the exponential term. This gives us 9 = 150e^(-0.1t).
Lastly, we can divide both sides of the equation by 150 to solve for e^(-0.1t). This gives us 0.06 = e^(-0.1t).
To solve for t, we can take the natural logarithm of both sides of the equation. This gives us ln(0.06) = -0.1t.
Finally, we can divide both sides of the equation by -0.1 to solve for t. This gives us t = ln(0.06) / -0.1.
Using a calculator to evaluate this expression, we find that t ≈ 5.06 days.