Mr Lamb is an old man with a tin leg. His real leg was blown off years ago during the war. He lives all alone in his house. There is a garden near the house. It has ripe crab apples looking orange and golden in colour. Mr Lamb is sitting in his garden when Derry climbs over the garden wall to get into his garden. Though the gate is open, the boy does not use it.

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?