# How Old is John Now Based on Past and Future Age Calculations?

• harpazo
In summary: Apparently it has a side effect of putting a strike-through effect on one's name. Strange.YOU ARE NOW ON MY IGNORE LIST.
harpazo
Homework Statement
Find John's current age using algebra.
Relevant Equations
x - 5 = (1/2)(x + 8)
Five years ago, John’s age was half of the age he will be in 8 years. How old is he now?

John's age now = x
John's age 5 years ago = x - 5
John's age in 8 years = x + 8

x - 5 = (1/2)(x + 8)

x - 5 = (x/2) + 4

2(x - 5) = 2[(x/2) + 4]

2x - 10 = x + 8

2x - x = 8 + 10

x = 18

John is currently 18 years old.

Let me check.

Let x = 18

18 - 5 = (1/2)(18 + 8)

13 = (1/2)(26)

13 = 13

It checks to be true.

Delta2
impeccable !

BvU said:
impeccable !
Not too bad. Of course, word problems will get increasingly harder as the weeks and months go on.

Be assured PF is there to help !

##\ ##

BvU said:
Be assured PF is there to help !

##\ ##
I really hope so. There are questions that I simply will not even know how to begin, which is pretty common.

harpazo said:
Homework Statement:: Find John's current age using algebra.
Relevant Equations:: x - 5 = (1/2)(x + 8)

Five years ago, John’s age was half of the age he will be in 8 years. How old is he now?

John's age now = x
John's age 5 years ago = x - 5
John's age in 8 years = x + 8

x - 5 = (1/2)(x + 8)

x - 5 = (x/2) + 4

2(x - 5) = 2[(x/2) + 4]

2x - 10 = x + 8

2x - x = 8 + 10

x = 18

John is currently 18 years old.

Let me check.

Let x = 18

18 - 5 = (1/2)(18 + 8)

13 = (1/2)(26)

13 = 13

It checks to be true.
I looked at this for the question and setup. It looks good; but I did not look carefully at the algebraic solving steps. I have not yet looked at the posts which followed.

symbolipoint said:
I looked at this for the question and setup. It looks good; but I did not look carefully at the algebraic solving steps. I have not yet looked at the posts which followed.
I hope to be right.

YOU ARE NOW ON MY IGNORE LIST.

Last edited:

BvU said:
Why?

harpazo said:
Why?
Apparently it has a side effect of putting a strike-through effect on one's name. Strange.

SammyS and Delta2
harpazo said:
YOU ARE NOW ON MY IGNORE LIST.
Who? Me? I am just trying to help!

## 1. How do you determine John's age?

John's age can be determined by asking him directly or by looking at official documents such as his birth certificate or government-issued identification.

## 2. Can you estimate John's age based on his appearance?

While it is possible to make a rough estimate of someone's age based on their appearance, it is not always accurate. Factors such as genetics, lifestyle, and health can all play a role in how someone looks at a certain age.

## 3. Is John's age important in a scientific context?

It depends on the specific context and research being conducted. In some cases, age may be a significant factor, while in others it may not be relevant at all.

## 4. Can you determine John's age through DNA testing?

DNA testing can provide information about an individual's genetic makeup, but it cannot determine their age. However, certain markers in DNA can give an estimate of someone's age range.

## 5. How does John's age affect his cognitive abilities?

Age can play a role in cognitive abilities, as certain functions may decline with age. However, this can vary greatly from person to person and is also influenced by factors such as education, lifestyle, and overall health.

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