Question

How many times does the digit 1 occur in ten's place in the number from 100 to 1000

Answer 1

We need to find the number of times the digit one appear in tens place from 100 to 1000

Tens place is the second digit from extreme right.

Let us consider the number of times it occurs from 100 to 200

The required numbers are 110,111,112,.....,119 (ten numbers)

Similarily there will be 10 such numbers from 200 to 300, 300 to 400 and so on untill 900 to 1000.

So the required answer is

9 x 10 = 90