Talk:Rooms/@comment-212.34.180.132-20190819093826/@comment-88.77.178.180-20191123103834

Because it does not include the original 100%. A lvl 5 mine rate manager multiplies your mine rate by 2.25 so the bonus is 1.25. If you multiply the bonus by 1.5 you get a bonus of 1.88 or a mutiplier of 2.88.