Set 6: Linear Functions

Explanation

Answer: A

A tank contains 100 gallons of water and drains at a rate of 5 gallons per minute. Which equation models the volume $V$ after $t$ minutes?

$V = -5t + 100$

✓ Correct

$V = 5t + 100$

$V = 100t - 5$

$V = -5t - 100$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Draining means negative slope. 1. Rate: Draining 5 gal/min $\rightarrow$ Slope is $-5$ . 2. Start: 100 gallons $\rightarrow$ Intercept is $+100$ . 3. Equation: $V = -5 t + 100$ . Strategic Tip: "Drains", "Falls", "Decreases" always imply a negative slope. Choice B is incorrect because it implies the tank is filling up. Choice C is incorrect because it swaps rate and start. Choice D is incorrect because it implies negative initial volume.

Key Steps:

•

The correct answer is $V = -5t + 100$

Why others are wrong:

B: Choice B is incorrect and may result from a calculation error.

C: Choice C is incorrect and may result from a calculation error.

D: Choice D is incorrect and may result from a calculation error.

← Previous Next →

🎯 Keep Practicing!

Master all sections for your best SAT score

📚Reading & Writing→📖Vocabulary→