Edexcel C3 2013 January — Question 8

Exam BoardEdexcel
ModuleC3 (Core Mathematics 3)
Year2013
SessionJanuary
TopicExponential Functions

  1. The value of Bob's car can be calculated from the formula
$$V = 17000 \mathrm { e } ^ { - 0.25 t } + 2000 \mathrm { e } ^ { - 0.5 t } + 500$$ where \(V\) is the value of the car in pounds \(( \pounds )\) and \(t\) is the age in years.
  1. Find the value of the car when \(t = 0\)
  2. Calculate the exact value of \(t\) when \(V = 9500\)
  3. Find the rate at which the value of the car is decreasing at the instant when \(t = 8\). Give your answer in pounds per year to the nearest pound.