$T=40 \,s$
If $t=2$ minute $20$ second
$=2 \times 60+20$
$=140 \,s$
So, it has completed $3 \frac{1}{2}$ revolution.
Distance travelled $=3 \times 2 \pi R+\pi R$ $=7 \pi R$
Displacement $=2 R$
$\frac{\mid \text { Displacement| }}{\text { Distance }}=\frac{2 R}{7 \pi R}=\frac{2}{7 \times \frac{22}{7}}=\frac{1}{11}$