Edexcel C4 — Question 1

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
TopicDifferential equations

  1. The number of people, \(n\), in a queue at a Post Office \(t\) minutes after it opens is modelled by the differential equation
$$\frac { \mathrm { d } n } { \mathrm {~d} t } = \mathrm { e } ^ { 0.5 t } - 5 , \quad t \geq 0$$
  1. Find, to the nearest second, the time when the model predicts that there will be the least number of people in the queue.
  2. Given that there are 20 people in the queue when the Post Office opens, solve the differential equation.
  3. Explain why this model would not be appropriate for large values of \(t\).