SOLUTION: Gabriel, Christian and Sebastian are friends whose ages add up to 26. Five years ago, Christian's age is twice that of Gabriel's. Seven years from now, Sebastian's age will be thir

Algebra.Com
Question 794949: Gabriel, Christian and Sebastian are friends whose ages add up to 26. Five years ago, Christian's age is twice that of Gabriel's. Seven years from now, Sebastian's age will be thirteen less than the sum of the ages of Gabriel and Christian. How old is Christian?
Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
Gabriel, Christian and Sebastian are friends whose ages add up to 26.
g + c + s = 26
Five years ago, Christian's age is twice that of Gabriel's.
c -5 = 2(g-5)
c-5 = 2g - 10
c = 2g - 10 + 5
c = 5g - 5
-2g + c = -5
Seven years from now, Sebastian's age will be thirteen less than the sum of the ages of Gabriel and Christian.
s + 7 = (c+7) + (g+7) - 13
s + 7 = c + g + 14 - 13
s = c + g + 1 - 7
s - c - g = -6
:
Arrange like the 1st equation and use elimination
-g - c + s = -6
g + c + s = 26
-----------------adding eliminates g and c, find s
2s = 20
s = 10 yrs is S's age
:
Using the 1st equation, and the rearanged 2nd equation:w
g + c = 16
-2g +c = -5
-----------------Subtraction eliminates c, find g
3g = 21
g = 7 yrs is G's age
:
How old is Christian?
g + c + s = 26
7 + c + 10 = 26
c = 26 - 17
c = 9 yrs is C's age

RELATED QUESTIONS

Christian is twice as old as Taskie while Dark is 24 years younger than Christian. If... (answered by josgarithmetic,MathTherapy)
5 years ago Christian was twice as old as Alec. The sum of their ages in 6 years will be... (answered by srinivas.g)
The sum of the ages of Gabriel and Ashton is 103 years. 9 years ago, Gabriel's age was 4... (answered by josgarithmetic)
Rian is 4 years older than Christian. Twelve years ago Rian was two times as old as... (answered by mike69)
When Christian and Cynthia were married, Cynthia was two years younger than Christian.... (answered by ikleyn)
1) CHRISTIAN IS 32 YEARS OLD AND HIS SON IS 5 YEARS OLD. HOW MANY YEARS FROM NOW WILL... (answered by srinivas)
megan is four years older than jacob, who is ten years older than christian. the sum of... (answered by ewatrrr)
This year Lyann is three times as old as Christian. if x represents Christians age... (answered by josmiceli)
The sum of Ellen’s and Todd’s ages is 34 years. Five years ago, the sum of twice... (answered by CubeyThePenguin,MathLover1)