Mathematics · Simple Interest

A person allocated savings for his 3 children in 3 different simple interest schemes such that each scheme pays the respective child at the age of 18. His son, who is 15 years old, gets 40% of the total savings; the elder daughter, who is 14 years old, gets 35%; and the younger daughter, who is 12 years old, gets the remainder. If all of them receive the exact same total interest upon turning 18, what is the ratio of the rates of interest of these 3 schemes?