Which of the following scenarios best describes linear growth? a. Water dripping from a leaking tap at a constant rate. b. Viral spread of a video online. c. Population doubling every 3 years. d. Spre

A linear growth model describes a situation where a quantity increases by a constant amount over equal intervals of time.

Let's analyze each option:

• a. Water dripping from a leaking tap at a constant rate: If water drips at a constant rate (e.g., 5 mL per minute), the total volume of water collected increases by 5 mL every minute. This is a constant additive increase, which is characteristic of linear growth.
• b. Viral spread of a video online: The spread of a viral video typically means that each person who sees it shares it with multiple others, leading to a rapid, accelerating increase in views. This is an example of exponential growth.
• c. Population doubling every 3 years: Doubling means the population is multiplied by a factor of 2 in a fixed time period. This is a constant multiplicative increase, which is characteristic of exponential growth.
• d. Spread of a contagious disease: Similar to viral spread, a contagious disease spreads exponentially as each infected individual can infect multiple new individuals.

Therefore, the example that best fits a linear growth model is water dripping at a constant rate.

$$\boxed{\text{a. Water dripping from a leaking tap at a constant rate}}$$