SOLUTION: In 10 years time Bill will be 30 years old. John will then be half of Bill's age. How old is John now? I did the problem, either 10 + ? (20) = 30 divide 2 = 15.. 20-15 = 5 bu

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Question 579924: In 10 years time Bill will be 30 years old. John will then be half of Bill's age. How old is John now?
I did the problem, either 10 + ? (20) = 30 divide 2 = 15.. 20-15 = 5 but how do you put it into picture form? Is this problem correct in form?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
In 10 years time Bill will be 30 years old.
John will then be half of Bill's age.
How old is John now?
:
I'm not sure what "picture form" is but we can do it this way.
:
let j = John's present age
Let b = Bill's present age
:
Write an equation for each statement:
:
"In 10 years time Bill will be 30 years old."
(b + 10) = 30
:
"John will then be half of Bill's age."
j + 10 = .5(b+10)
:
From the 1st equation we can replace (b+10) with 30
j + 10 = .5(30)
j + 10 = 15
j = 15 -10
j = 5 yrs is John's present age