Question 1099387: the sum of the age of four sisters is 30. the sum of their ages four years ago was 15. how old is the youngest sister? Answer by KMST(5328) (Show Source):
You can put this solution on YOUR website! The youngest sister is years old.
Four years ago there were only 3 sisters, whose ages added up to 15.
Each of those sisters is 4 years older now,
so naturally, the sum of the ages of those 3 sisters has increased by
to .
A new sister was born, who is now years old,
so now the sum of the sisters' ages is .