You start off with i equal to 11.
Your code will run adding 3 to i as long as i is less than or equal to 99
when i is greater than 99 it drops out of loop and outputs result
so what is happening is is your code will continue to add 3 to i until it is greater than 99.
So i starts off at 11 and eventually equals 98, and 98<99 so the code runs 98+3=101. 101 is not less than or equal to 99 so it drops out of the loop and outputs the value of 101.