SOLUTION: The sum of the present ages of john and his father is 89 years. After 11 years the age of father will be twice the age of john at that time, find their present ages.

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Question 434074: The sum of the present ages of john and his father is 89 years. After 11 years the age of father will be twice the age of john at that time, find their present ages.
Found 5 solutions by mananth, jane.manuel, ikleyn, josgarithmetic, greenestamps:
Answer by mananth(16949)   (Show Source):
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john's age =x
father's age = 89-x
..
after 11 years
john's age = x+11
father's age = 99-x
...
99-x=2(x+11)
99-x=2x+22
99-22=2x-x
77=x fathers age
12 = sons age

Answer by jane.manuel(1)   (Show Source):
You can put this solution on YOUR website!
ANSWER:
father's present age is : 63
john's present age is : 26

add 63 and 26 and the result is 89.

add 11 years to john's age : 26 + 11 = 37
add 11 years to Father's age : 63 + 11 = 74

multipLy the age of John after 11 years by 2 : 37 x 2 = 74

so his father's age is twice the age of John after 11 years. ^_^

Answer by ikleyn(53427)   (Show Source):
You can put this solution on YOUR website!
.
The sum of the present ages of john and his father is 89 years.
After 11 years the age of father will be twice the age of john at that time,
find their present ages.
~~~~~~~~~~~~~~~~~

        The solution in the post by @mananth is incorrect.
        His setup and his treatment of equations is erroneous and leads right to abyss.
        I came to make a job accurately and to teach you properly.

john's age =x
father's age = 89-x
..
after 11 years
john's age = x+11
father's age = (89-x)+11 = 100 - x
...
100 - x = 2(x+11)
100 - x = 2x + 22
100 - 22 = 2x + x
78 = 3x
x = 78/3 = 26.

ANSWER. John is 26 years old. The father is 89-26 = 63 years old.

Solved correctly.

Answer by josgarithmetic(39702)   (Show Source):
You can put this solution on YOUR website!

NOW IN 11 YEARS John 89-m 89-m+11=100-m Father m m+11 SUM 89 89+2*11=111

Description makes that .

John's Father, 63
John, 26

Answer by greenestamps(13258)   (Show Source):
You can put this solution on YOUR website!

Given that John's father will be twice as old as John is 11 years from now....

let x = John's age 11 years from now
then 2x = father's age 11 years from now
then x-11 = John's age now
and 2x-11 = father's age now

The sum of their present ages is 89:

(x-11)+(2x-11) = 89
3x-22 = 89
3x = 111
x = 37

John's present age = x-11 = 37-11 = 26
father's present age = 2x-11 = 74-11 = 63

ANSWERS: 26 and 63

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I chose to set the problem up in a different way than the other tutors.

Sometimes that can make a big difference in how much work it takes to solve the problem.

It didn't make much difference in this problem....