\( 10 \) divisions on the main scale of a vernier calliper coincide with \( 11 \) divisions on the Vernier scale. If each division on the main scale is of \( 5 \) units, the least count of the instrument is:
\( \frac{5}{11} \)
\( \frac{10}{11} \)
\( \frac{1}{2} \)
\( \frac{50}{11} \)