The percentage of numbers from 1 to 70 that have 1 or 9 in the unit's digit is 20%. Explanation:
- Numbers with 1 in the unit's digit between 1 to 70: 1, 11, 21, 31, 41, 51, 61 (7 numbers)
- Numbers with 9 in the unit's digit between 1 to 70: 9, 19, 29, 39, 49, 59, 69 (7 numbers)
- Total numbers with either 1 or 9 in the unit's digit: 14
- Total numbers from 1 to 70: 70
- Percentage = (14 / 70) × 100 = 20%
