In a metal cutting operating, the following equation for tool-life was obtained for H.S.S. tool:
V T0.13 f0.6 t0.3 = C.
Given that: tool-life(T) = 60 min,
Cutting speed (V) = 40 m/min,
Feed (f) 0.25 mm/rev,
Depth of cut (t) = 2.0
Compute tool-life, if speed, feed and depth of cut are together increased by 25% and also if they are increased individually by 25%.