Answer
$6.5cm$
Work Step by Step
Second hand completes 1 cycle in 1 min. So it rotates $30\times 2\times pi=60pi \,\,rad$
Length of second hand =0.35m, distance travelled =$0.35\times 60pi=66m$
Minute hand completes 1 cycle in 1 min. In 30 mins, it rotates $180^{\circ}=pi \,\,rad$.
Length of minute hand is $0.3m$. So distance travelled by minute hand $=pi\times0.3=0.94m$
Hour hand rotates $15^{\circ}=\frac{pi}{12} rad$ in 30 mins. Length of hour hand is 0.25m. So, the distance travelled by hour hand =$0.25\times\frac{pi}{12} =0.065m=6.5cm$
