Question

If you write down all the numbers from $1$ to $100$, then how many times do you write $3$?

• A. $11$
• B. $18$
• C. $20$
• D. $21$

Answer 1

The correct option is C $20$

Clearly, from $1$ to $100$, there are ten numbers with $3$ as the unit's digit - $3,13,23,33,43,53,63,73,83,93$;
and ten numbers with 3 as the ten's digit - $30,31,32,33,34,35,36,37,38,39$.
So, required number $=10+10=20$.