Question 1168745: Sherry is half as old as her mother. Twelve years ago, she was one third of her mother’s age. Find their ages
now.
CAN YOU ALSO PLEASE USE THE GUESS MEHTOD
THANK YOU
Found 3 solutions by Theo, josgarithmetic, MathTherapy:
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! guess method.
given
unknowns
equations
setup
solve
given:
sherry is half as old as her mother.
twelve years ago, she was one third the age of her mother.
unknown:
what are both their ages now?
equations:
let s = sherry's age now.
let m = her mother's age now.
today she is half as old as her mother.
s = 1/2 * m
twelve years ago, she was one third the age of her mother.
s - 12 = 1/3 * (m - 12)
setup:
these are two equations that need to be solved simultaneously
they are:
s = 1/2 * m
s - 12 = 1/3 * (m - 12)
solve:
in the second equation, replace s with 1/2 * m from the first equation to get:
1/2 * m - 12 = 1/3 * (m - 12)
simplify to get:
1/2 * m - 12 = 1/3 * m - 4
add 12 to both sides of the equation and subtract 1/3 * m from both sides of the equation to get:
1/2 * m - 1/3 * m = -4 + 12
put everything on the left hand side of the equation under a common denominator to get:
3/6 * m - 2/6 * m = -4 + 12
simplify to get:
1/6 * m = 8
solve for m to get:
m = 8 * 6/1 = 48
solution:
sherry is 24 years old now and her mother is 48 years old now.
confirmation:
sherry is now 1/2 the age of her mother (24/48 = 1/2)
12 years ago, sherry was 12 and her mother was 36.
sherry was 1/3 the ages of her mother 12 years ago (12/36 = 1/3)
Answer by josgarithmetic(39617)  (Show Source):
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website!
Sherry is half as old as her mother. Twelve years ago, she was one third of her mother’s age. Find their ages
now.
CAN YOU ALSO PLEASE USE THE GUESS MEHTOD
THANK YOU
Let daughter's age be D
Then mother's is: 2D
Three years ago, mother was THREE times daughter's age
We then get: 2D - 12 = 3(D - 12)
2D - 12 = 3D - 36
2D - 3D = - 36 + 12
- D = - 24
Daughter's age, or 
You should now be able to find mother's age!!
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