The way Charley came across Sam’s letter was surrounded in mystery. Among his oldest first-day covers, he found an envelope. The envelope containing the letter bore the address of his grandfather. It was written on July 18, 1894. The postmark showed the Picture of President Garfield. Generally the first day covers have blank papers in them, but this one contained a letter. The letter was addressed to Charley. In the letter Sam had informed Charley that he was living on the third level. He had also told Charley and his wife to keep looking for the third level. Clearly, the letter was a product of Charley’s imagination.

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?