9
QuizMultiple Choice

Composition of Functions and Modeling — Quiz

Question 9 • Precalculus

The radius of a sphere-shaped balloon increases at a rate of 2 centimeters cm per second. If the surface area of the completely inflated balloon is 784 pi cm squared , how long will it take for the balloon to fully inflate? Use cap s cap A is equal to 4 pi r squared

Answer
A
196 seconds
B
49 seconds
C
7 seconds
D
10 seconds

Explanation

Use the surface-area formula, SA = 4πr². Set 4πr² = 784π, so r² = 196 and the balloon’s final radius is 14 cm. At 2 cm per second, reaching 14 cm takes 14 ÷ 2 = 7 seconds, so the correct choice is 7 seconds.

AI-written and checked against the verified answer.

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