Question

In the natural numbers from $10$ to $250$, how many are divisible by $4$?

Answer 1

Let a be first term & d be the common difference

a=12

d=14

$a_n=248$

$a_n=a+(n-1)d$

$248=12+(n-1)4$

$\Rightarrow 248-12=4(n-1)$

$\Rightarrow 236=4n-4$

$\Rightarrow 240=4n$

$\Rightarrow n=60$

$\therefore$ There are 60 numbers between 10 & 250 that are divisible by 4.