Question 690739: My sister is 5 years older than I , the sum of our ages equals 35 ,
what is my age and my sisters ? Answer by mouk(232) (Show Source):
You can put this solution on YOUR website! Let s = sisters age
and y = your age
then, "My sister is 5 years older than I" ==> s = y + 5 Eq (1)
and "the sum of our ages equals 35" ==> s + y = 35 Eq (2)
Substituting s = y + 5 into Eq (2) gives:
(y + 5) + y = 35
2y + 5 =35
2y = 30
y = 15
Substituting y = 15 into Eq (1) gives:
s = 15 + 5
s = 20
So your age is 15, your sisters age is 20