SOLUTION: Travis is 21 years older than his sister Michelle. In 9 years, he will be twice as old as Michelle. How old is each of them now?

Question 1113116: Travis is 21 years older than his sister Michelle. In 9 years, he will be twice as old as Michelle. How old is each of them now?
Found 2 solutions by stanbon, greenestamps:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Travis is 21 years older than his sister Michelle. In 9 years, he will be twice as old as Michelle. How old is each of them now?
------------------
Equations:
T = M + 21
T+9 = 2(M+9)
--------
Substitute for "T" and solve for "M":
M+21+9 = 2M + 18
-----
M + 30 = 2M+18
M = 12 (Michelle's age now)
-------------
T = M + 21 = 33 (Travis's age now)
-------------
Cheers,
Stan H.
------------
Answer by greenestamps(13200) (Show Source): You can put this solution on YOUR website!

You can solve this without formal algebra by using logical reasoning.

Travis will always be 21 years older than is sister.
He will be twice as old as his sister when she is 21 and he is 42.
The problem says that will happen 9 years from now, so his age now is 42-9 = 33.
RELATED QUESTIONS
Mark is 20 years older than his sister michelle. In 4 years he will be Twice as old as... (answered by josmiceli)
Travis is 24 years older than his sister Danielle. In 13 years, he will be twice (answered by stanbon,Alan3354)
tony is 21 years older than his sister. in 10 years he will be twice as old as his... (answered by stanbon)
Jason is 21 years older than his sister Sarah. In 5 years he will be twice as old as... (answered by Maths68)
Ray is 21 years older than his sister Mary. In 7 years, he will be twice as old as Mary.... (answered by Alan3354)
Jason is 21 years older than his sister coral. In nine years he will be twice as old as... (answered by josgarithmetic)
Mark is 23 years older than his sister Ann. In 9 years, he will be twice as old as Ann.... (answered by mananth)
michelle is 19 years older than her brother doug. 6 years fro now, michelle will be twice (answered by scott8148)
Doug is 12 years older than his sister Linda. in 4 years ,he will be twice as old as... (answered by edjones)