CAPE Pure Mathematics Unit 1 · May/June 2012 · Paper 1 · Question Q43

The displacement, s metres, of a marble moving along a board at time t minutes is given by s(t) = 4t^3 - 30t^2 + 72t + 7 for t \ge 0. For what values of t is the displacement of the marble increasing?

1. (A)t < 2
2. (B)t > 3
3. (C)2 < t < 3
4. (D)t < 2 or t > 3