The focal lengths of objective and eye piece of a Galilean telescope are respectively 30 cm and 5 cm. Calculate its magnifying power and length when used to view distant object.

The focal lengths of the objective and the eye-piece of an astronomical telescope are $75 \mathrm{cm}$ and $5 \mathrm{cm}$ respectively. Calculate the magnifying power and the length of the telescope when the final image is formed at least distance of distinct vision ($25 \mathrm{cm}$)