The only occasion when Sophie got to see Danny Casey in person was when the family went to watch United on Saturday. Sophie, her father and little Derek went down near the goal. Geoff went with his mates higher up. United won two-nil. Her idol Casey drove in the second goal. She saw the Irish genius going round two big defenders on the edge of penalty area. He beat the hesitant goal keeper from a dozen yards. Sophie glowed with pride.

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?