SOLUTION: Mary, Melinda and Monica are sisters. The mean age is 12. Mary is 4 years older than Melinda. Monica is 1/2 the age of Mary. How old are they?

Question 1091997: Mary, Melinda and Monica are sisters. The mean age is 12. Mary is 4 years older than Melinda. Monica is 1/2 the age of Mary. How old are they?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = Mary's age now
Let = Melinda's age now
Let = Monica's age now
-------------------------------
(1)
(2)
(3)
-------------------------------
There are 3 equations and 3 unknowns,
so it is solvable
(2)
Substitute (2) and (3) into (1)
(1)
(1)
(1)
(1)
(1)
and
(2)
(2)
(2)
and
(3)
(3)
(3)
--------------------
Mary is 16
Melinda is 12
Monica is 8
--------------------
check:
(1)
(1)
(1)
(1)
OK
RELATED QUESTIONS
at the moment john is 5 years older than mary. in seven years mary age will be 3/4 of... (answered by lwsshak3)

the sum of john's age and Mary's age is 36 years. John is 4 years younger than Mary. how... (answered by Math_Boss)

find the age of john and mary if four times jonhs age equals three times marys age, and... (answered by jorel1380)

The sum of the ages of Barbara-Sue, Frank, and Mary is 300. And here are the ages: Mary... (answered by Boreal)

Mary is twice the sum of Sally's age and 2 years. If Mary is 12, how old is... (answered by ankor@dixie-net.com)

Tom is shorter than Mary and older than Joe. Mary is shorter than Joe but older than Tom. (answered by ankor@dixie-net.com)

Mary is ten years younger than twice Susan's age. Five years from now, Mary will be eight (answered by solver91311)

Rephrase this problem. If Larry is 12 years older than Mary, then Mary is what in terms... (answered by ikleyn)

Mary, Jane and Gloria are sisters. Mary is one year younger than the sum of janes and... (answered by JulietG)