A man in his deathbed fixed all his savings for his 3 children in 3 different schemes in such a way that each scheme will pay the respective child at their age of 18. His son, who is 15 years old gets 40%, elder daughter, who is 14 years old got 35% and younger daughter, who is 12 years old got the rest. If all of them got the same interest at their age of 18, what is the ratio of the rate of interest of those 3 schemes? (Assume all the schemes pay in simple interest)