2026 IGCSE Additional Mathematics February/March 0606/22 Q7

2026 IGCSE Additional Mathematics February/March 0606/22 Q7

8 marks

A ship is sailing with speed \(v\text{ km h}^{-1}\).

The sailing cost per hour, \(\$C\), is given by \(C=v^2+\dfrac{3000}{v}+100\).

  1. Find the speed that makes \(C\) a minimum.
    Justify that this value of \(C\) is a minimum.[5]
  2. Hence find the minimum sailing cost for a journey of 150 km.[3]

Solution:

Solution locked

Sign in to view the step-by-step solution

Similar questions are unavailable for this question.
Answer:(a) \(11.4\text{ km h}^{-1}\) (b) \(\$6460\) using the speed from (a), as in the official mark scheme. The unrestricted minimum journey cost is \(\$4875\); see the wording note.

Need help? Join our JC Math tuition classes.

Learn more