Question 313356: A father is 4 times his son’s age and in 30 years, son’s age will be half of his father’s age. How old are they now?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A father is 4 times his son’s age and in 30 years, son’s age will be half of his father’s age.
How old are they now.
:
Write an equation for each statement:
:
"A father is 4 times his son’s age"
f = 4s
:
"and in 30 years, son’s age will be half of his father’s age."
s + 30 = .5(f + 30)
s + 30 = .5f + 15
s = .5f + 15 - 30
s = .5f - 15
Replace f with 4s
s = .5(4s) - 15
s = 2s - 15
15 = 2s - s
15 = s
:
How old are they now?
son = 15 yrs, father: 4(15) = 60 yrs
:
:
Check solution in the statement:
"in 30 years, son’s age will be half of his father’s age."
15 + 30 .5(60 + 30)
45 = .5(90)
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