Find the sum of integers which are divisible by 5 from 1 to 100.

Given, Sum of integers from 1 to 100

Need to find out the numbers which are divisible by 5.

The numbers which are divisible by 5 are 5,10,15…..100

⇒ Now, Sum of integers form 1 to N =

Sum of integers from 1 to 100 divisible by 5

= (5 + 10 + ….. + 100)

= 5(1 + 2 + …. + 20)

= (5 × 10 × 21)

= 1050

Hence, the sum of integers which are divisible by 5 from 1 to 100 is 1050.