SOLUTION: five years ago Jacob was one sixth of the age of his brother. In three years time his ager doubled will match his brother age. How old is Jacob now?

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Question 1150954: five years ago Jacob was one sixth of the age of his brother. In three years time his ager doubled will match his brother age. How old is Jacob now?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Let j = Jacob's present age
let b = brother's " "
:
Write an equation for each statement
:
five years ago Jacob was one sixth of the age of his brother.
j - 5 = 1%2F6(b-5)
j = 1%2F6(b-5) + 5
multiply by 6 to get rid of the fraction
6j = b - 5 + 30
6j = b + 25
or we could write
b = 6j - 25
In three years time, his age doubled, will match his brother age.
b + 3 = 2(j+3)
b + 3 = 2j + 6
b = 2j + 6 - 3
b = 2j + 3
replace b with (6j-25)
6j - 25 = 2j + 3
6j - 2j = 3 + 25
4j = 28
j = 28/4
j = 7 yrs is Jacob's present age
:
:
Check this, find b
b = 2(7) + 3
b = 17
Check in the statement
" In three years time his age doubled will match his brother age.
2(7+3) = 17 + 3
2(10) = 20