How many odd five-digit counting numbers can be formed by choosing digits from the set {1, 2, 3, 4, 5, 6, 7, 8} if digits can be repeated?
Digits = 1, 2, 3, 4, 5, 6, 7, 8 and can be repeated.
1's digit has = 4 possibilities
Rest all digits have 8 possibilities
No. of 5-digit numbers = 8 × 8 × 8 × 8 × 4 = 16384