Question

A man wrote all the natural numbers starting from 1 in a series. What will be the ${50}^{th}digitofthenumber?$

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is C 3

123....910.....
One digit numbers (from 1 to 9) = 9
Now digit number till 50 are 50 - 9 = 41 thus
total digits used to make pair.
$\underset{–}{10}\underset{–}{11}\underset{–}{12}....29.$
So total $20\times 2=40$ digits would be required to write number from 10 to 29.
Total digits consumed so far till we write 29 will be 9 + 40 = 49.
${50}^{th}\text{digit which we will write is 3 of 30.}$

$Hence{50}^{th}digitwillbe3.$

49 digits are used, So far till 29.
$Now,{50}^{th}\text{digit would be first digit of 30 thus 3.}$