How many times fainter (or brighter) will 100 stars of the same luminosity, distant at a distance of 5r

How many times fainter (or brighter) will 100 stars of the same luminosity, distant at a distance of 5r, shine compared to one such star at a distance of r?

The brightness of a group of stars is proportional to their number and inversely proportional to the square of the distance E2 / E1 = (n2 / n1) * (r1 / r2) ^ 2, (4 points) in our case we get E2 / E1 = 100/5 ^ 2 = 4 -group of stars will be 4 times brighter.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.