Question

The number of two digit numbers which are divisible by $3$ are

• A. $33$
• B. $31$
• C. $30$
• D. $29$

Answer 1

The correct option is C $30$

Two digit numbers which are divisible by $3$ are $12,15,\mathrm{18...99}$;
It forms an A.P. with first term $12$ and common difference $3$.
So, $99=12+(n-1)\times 3$
$\Rightarrow n=30$