What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?
Show answer & explanation
Correct answer: C
Explanation
Total numbers from 1 to 70 = 70
Numbers with 1 as the unit digit:
1, 11, 21, 31, 41, 51, 61 = 7
Numbers with 9 as the unit digit:
9, 19, 29, 39, 49, 59, 69 = 7
Total numbers = 7 + 7 = 14
Percentage = 14/70 × 100 = 20%