Give the cutting speed = 9 m/min, the return time to cutting time ratio is = 1:2 the feed rate = 0.3 mm/stroke, the clearance at each of cut = 25 mm and that the plate is fixed 700 mm side along the direction of tool travel, the time required for finishing one flat surfaces of a plate of size 700 × 30 mm in a shaper, will be
(a) 10 min (b) 12.5 min
(c) 15 min (d) 20 min