1. The problem statement, all variables and given/known data The number of stars around the Sun, within a distance of 17 ly, is 75. The number of galaxies in the local group, within a distance of 4.0 x106 ly from the Sun, is 26. Calculate the average popluation density, per ly3, of stars and galaxies. 2. Relevant equations 3. The attempt at a solution Stars: 75/173 Galaxies: 26/(4.0 x106)3 But the answers I obtain from my attempt is incorrect :s Help please!