PLEASE help with this astronomy question!!!!!?

Question

A Cepheid variable is 100 times brighter than a typical RR Lyrae star. How much farther away than the RR Lyrae stars can Cepheids be used as distance-measuring tools?

Answer 1

Ten times farther away. Visible brightness drops as the square of the distance.

Answer 2

if you can see it you can use it. how much further away can you see a star that is 100 times brighter?