WAEC 2020 · Paper 1 · Q32
A three-digit odd number less than 500 is to be formed from 1, 2, 3, 4 and 5. If repetition of digits is allowed, in how many ways can this be done?
Worked solution (try it first)
- First digit: less than 500 means it is 1, 2, 3 or 4, so 4 choices.
- Middle digit: any of the 5 digits (repetition allowed), so 5 choices.
- Last digit: odd means 1, 3 or 5, so 3 choices.
- Multiply: ways, option C.