The quick return ratio of the mechanism is

Question

The crank and slotted lever quick – return motion mechanism is shown in figure. The length of links $O_{1}O_{2}O_{1}$ and $O_{2}A$ are 10cm, 20cm and 5cm respectively.

The quick return ratio of the mechanism is

 (a) 3.0     (b) 2.75    (c) 2.5      (d) 2.0