Model and Reason with Equations and Inequalities: Part Two — Test
Question 6 • Algebra II
The height of a stuntperson jumping off a building that is 20 m high is modeled by the equation h is equal to 20 minus 5 t squared , where t is the time in seconds. A high-speed camera is ready to film the person between 15 m and 10 m above the ground. For which interval of time should the camera film the person?
Answer
A
1 is less than t comma t is less than square root of 2
B
t is equal to square root of 2
C
t is less than 2
D
t is greater than square root of 2
Explanation
The camera should film while the person is between 10 m and 15 m high, so solve 10 < 20 − 5t² < 15. These inequalities give t² < 2 and t² > 1; since time is positive, 1 < t < √2. Therefore, the correct choice is A, from 1 second to √2 seconds.
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