4. A man decides to plant a number of fast-growing trees as a boundary between his property and the property of his next door neighbour. He has been warned, however, by the local garden centre that, during any year, the trees are expected to increase in height by 0.5 metres. In response to this warning he decides to trim 20% off the height of the trees at the start of any year.
(a) If he adopts the "20% pruning policy", to what height will he expect the trees to grow in the long run?
(b) His neighbour is concerned that the trees are growing at an alarming rate and wants assurances that the trees will grow no taller than 2 metres. What is the minimum percentage that the trees will need to be trimmed each year so as to meet this condition?
In part (a) the only thing I could see to do was find the limit which I did and got 2.5 - which was the correct answer. Im just stuck on b) and wondering if anyone could explain this?
Thanks
