I would let the student identify what the important elements of the question are and encourage them to assign each with a term or other mathematical notation. I would then go through these to make sure the student understood what terms such as rate of increase/decrease mean in mathematical notation. This should make a seemingly wordy question appear a lot simpler however, if the student was still struggling to answer the question, I would give them hints towards the right answer like 'what does the rate of change being proportional to that term mean?' until the student understands. I would then encourage the student to try a different question to ensure that they could repeat the process.
With this type of question I would always ensure the student started on one that was phrased show that as this gives them immediate confirmation that their answer is correct.