Easy Tutorial
For Competitive Exams

What percentage of numbers from 1 to 70 have 1 or 9 in the units digit?

1
14
20
21
Explanation:

Clearly, the numbers which have 1 or 9 in the units digit, have squares that end in the digit 1.

Such numbers from 1 to 70 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.

Number of such number =14

$\therefore$ Required percentage =$ \left(\dfrac{14}{70} \times 100\right) $% = 20%.

Share with Friends
Privacy Copyright Contact Us