8
practice testMultiple Choice

Practice Test

Question 8 • Mathematics 8

Harold wrote this equation to model the level of water in a pool over time. The variable x represents time in hours. f⁡(x)=3,500−225⁢x Which statements about the situation are true? Choose three correct answers.

Answer
A
The pool was empty after 14 hours.
B
The water level is rising.
C
The water was 2 comma 600 units high after 4 hours.
D
The initial level of water in the pool was 225 units.
E
The initial level of water in the pool was 3 comma 500 units.
F
The water level is falling.

Explanation

At 4 hours, the model gives f(4) = 3,500 − 225(4) = 2,600, so the water is 2,600 units high (C). At time 0, the level is f(0) = 3,500, making 3,500 units the initial level (E). The negative coefficient, −225, means the water level falls by 225 units each hour (F).

AI-written and checked against the verified answer.

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