The sum of integers from 1 to 100 that are divisible by 2 or 5 is
Number divisible by 2 = even numbers between 1 and 100 (both inclusive)
Sum of even numbers =
Now, numbers divisible by 5 either end in 5 or 0.
But the numbers ending in 0 are also divisible by 2.
Sum of numbers ending in 5 =
Therefore, required sum =