\text { where } 0 \leq t \leq 24 Note: t = hours after installation. (a) What is the initial humidity level in the room? (b) How long will it take for the humidity to reach a level of 40g/m³. (c) Find the derivative of h(t). (Show detailed working or explain your answer.) (d) Explain what the derivative of h(t) gives in this situation.

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