Cylindrical workpieces of diameter 60 mm and length 400 mm are machined on a lathe at a cutting speed of $25 \mathrm{~m} \mathrm{~min}^{-1}$ and a feed of $0.2 \mathrm{~mm} \mathrm{rev}^{-1}$. The Taylor's tool life parameters $C$ and $n$ for this setup are 75 and 0.25 , respectively. The tool changing time is 3 minutes. With a labor and overhead cost of Rs. 5 per minute, the tool changing cost per piece is Rs. ___________ (rounded off to 2 decimal places).

A flat surface of a C60 steel having dimensions of 100 mm (length) × 200 mm (width) is produced by a HSS slab mill cutter. The 8-toothed cutter has 100 mm diameter and 200 mm width. The feed per tooth is 0.1 mm, cutting velocity is 20 m/min and depth of cut is 2 mm. The machining time required to remove the entire stock is ____________ minutes (rounded off to 2 decimal places).