SOLUTION: tommy is twice is old as his younger sister. the sum of the siblings ages is 21. what equation can be used to determine the age of tommys younger sister?

Question 1066815: tommy is twice is old as his younger sister. the sum of the siblings ages is 21. what equation can be used to determine the age of tommys younger sister?
Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!

tommy is twice is old as his younger sister. the sum of the siblings ages is 21. what equation can be used to determine the age of tommys younger sister?
------
t = 2s
t + s = 21
------
Equation::
(t/2) + s = 21
---------------------
Cheers,
Stan H.
-----------
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.
x + 2x = 21.

RELATED QUESTIONS
Tommy is 4 years older than his sister, Candace. The product of their ages is 96. How old (answered by MathLover1)
Bill, Phil, and Jenny are siblings. Bill is twice as old as Phil. Jenny is two years... (answered by ikleyn)
The sum of the ages of two sisters is 12 years,with the elder sister twice as old as the... (answered by Alan3354)
Hello: I am trying to solve this problem, but i am having a hard time setting up the... (answered by rfer,ankor@dixie-net.com)
Zachary is 1 year older than his sister, Nicole. Jaycob is three times as old as Zachary. (answered by ikleyn)
Gabrielle's oldest brother Jake is twice her age, and her younger sister Candi is... (answered by josgarithmetic)
How old are they if tommy was twice as old as Eric and James is three-quarters the age of (answered by jorel1380)
Tom is five years older than his sister Melissa, and three times the sum of the ages of... (answered by ankor@dixie-net.com)
Sarah is 5 years older than her sister hanna. Jim is twice as old as his sister hanna.... (answered by josmiceli,macston)