SOLUTION: A mother is 4 times as old as her son and in twenty years will be twice as old as her daughter, who is five years older than her brother. How old is each?

Question 154828: A mother is 4 times as old as her son and in twenty years will be twice as old as her daughter, who is five years older than her brother. How old is each?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
: A mother is 4 times as old as her son and in twenty years will be twice as
old as her daughter, who is five years older than her brother. How old is each?
:
Let their present ages = m, b, s; for mother, brother, and sister
:
write an equation for the given statements:
"A mother is 4 times as old as her son"
m = 4b
:
"in twenty years (she) will be twice as old as her daughter,"
m + 20 = 2(s+20)
m + 20 = 2s + 40
m - 2s = 40 - 20
m - 2s = 20
:
"who is five years older than her brother."
s = (b + 5)
:
How old is each?:
:
In the equation: m - 2s = 20:
substitute 4b for m and (b+5) for s
4b - 2(b+5) = 20
4b - 2b - 10 = 20
2b = 20 + 10
2b = 30
b =
b = 15 is the brothers age
:
you can find the other ages using the equations for m and s,
Check your solutions in the statement:
"In twenty years mother will be twice as old as her daughter,
:
:
Let me know if you have any questions about this?
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