A Cepheid variable star has an apparent brightness of 85 and a period of 14.3 days. (This means the star is 85 times brighter than the Sun would appear at a distance of 1 Mpc.) About how far away is the star?
a) 4.3 Mpc
b) 7.7 Mpc
c) 10.8 Mpc
d) 15.9 Mpc
