• # question_answer The ratio of time of return stroke to time of forward stroke of a shaping machine is 0.6. The stroke is 250 mm and it makes 30 double strokes per minute. What is the overall average speed of operation? A) 3.75 m/min                   B) 5.0 m/minC) 7.5 m/min                     D) 12 m/min

Average speed of operation $=\frac{2NL}{{{10}^{3}}}=\frac{30\times 250}{{{10}^{3}}}$  $=\text{ }7.5\text{ }m/min$