Question

How many numbers between 500 and 1000 are divisible by 13 ?

Answer 1

First number after 500 and divisible by 13 = 507 and number just less than 1000 and divisible by 13 = 998

Hence sequence

$507,520,.........,988\left(nterms\right)$

$\therefore 988=507+(n-1)13$

$\therefore (n-1)=481/17=37$

$n=38$

So, there are 38 numbers between 500 & 1000 which are divisible by 13.