Which of the following file is commonly used for die sinking, engraving and in silversmith's work?

41) Calculate the number of cutting stroke per minute in a shaping machine having a speed ratio of 2:3. (cutting speed = 20 m/min, length of stroke = 180mm)

42) In a slotting work, the length of the stroke is 300mm, number of double stroke per minute is 40, and the ratio of return time to cutting time is 2:3, find the cutting speed.

43) Calculate the feed in mm/min for a 75 dia, six-teeth helical carbide milling cutter when machining a cast iron work piece (take cutting speed = 60 m/min and chip per tooth = 0.2)

44) A sum fetched a total simple interest of Rs. 990 at the rate of 9% p.a. in 5 years. What is the sum?