There are five possible digits to chose from (5, 6, 7, 8, 9), and digits may be repeated, so there are 5 possible digits to chose from for each of the three places in a three digit number.
Therefore there are 5 x 5 x 5 = 125 3-digit numbers that can be formed from 5, 6, 7, 8, 9 if digits can be repeated.
