Question

Find the sum of all three digit numbers , which are divisible by 4

Answer 1

I hope it will help u

Answer 2

Here is the solution :

First, Let us find the smallest and the greatest 3 digit numbers which are divisible by 4,

Smallest 3 digit number divisible by 4 = 100,
Greatest 3 digit number divisible by 4 = 996,

Now,
Using A.P, Let us form an sequence,

=> Series : 100,104,108.........,996

Here,
The first term = 100 = a,
Last term = 996 = l,

Common difference = 104-100 = 4 = d,

No.of terms = ?
Nth term = a +(n-1)d
=> 996 = 100 + (n-1)4
=> 896/4 = n-1,
=> n = 225,

Which means there are 225 , Three digit numbers that are divisible by 4,

Now,
Sum of n terms of A.P can be calculated by using this formula,

Sum = (n/2)(a+l)
=> Sum = (225/2)(100+996)
=> Sum = (225)(1096/2)
=> Sum = 123,300,

Therefore : The sum of all 3 digit numbers that are divisible by 4, is, 123300,

Hope you understand, Have a great day !
Thanking you, Bunti 360 !!