Problem Solving (PS) | Re: According to a certain estimate, the depth N(t), in centimeters, of

This is beyond the scope of what's tested on the GMAT, but using derivatives, we can answer this in 15 seconds. The derivative will always be where the quadratic is at its maximum.

Given: \(N(t) = -20 (t-5)^2 + 500\)
Take the derivative: (t-5) = 0
Solve: t = 5
Plug into prompt: 2:00 am + 5 hours = 7:00 am

Answer: B

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