We have been given \(A = \frac{15c}{t^2}\)

where c is a constant, t is the time after explosion, and A is the speed of the particle, in feet per second(at t time after the explosion)

Since, the speed is 450 ft/s at t=2,

substituting these values,

\(450 = \frac{15*c}{2^2}\)

Constant(c) = \(\frac{450 * 4}{15} = 30 * 4 =120\)

Now, we have been asked to find A given t=3

Therefore A(when t=3) = \(\frac{15*120}{3^2} = 5*40 = 200\)(Option D)

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