How Old is Lee Based on the Given Mathematical Problem?

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In summary: Therefore, Lee is 7 years old.In summary, Lee has an older sister and a younger sister. Her older sister is one year more than twice Lee's age. Lee's younger sister is three years younger than she is. The sum of their three ages is 26. Based on the equation, Lee's age is 7 years old.
  • #1
mathdad
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Lee has an older sister and a younger sister. Her older sister is one year more than twice Lee's age. Lee's younger sister is three years younger than she is. The sum of their three ages is 26. Find Lee's age?

My equation set up is

x + (2x + 1) + (2x + 1) - 3 = 26

This equation yields a fraction answer which is not possible in terms of age.

My answer is 27/5 as Lee's age.This cannot be right. What do you say?
 
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  • #2
Hi RTCNTC,

It's important to write down what your variables represent. If $x$ represents Lee's age, then $x - 3$, not $(2x + 1) - 3$, represents the age of Lee's younger sister. The equation is then

$$x + (2x + 1) + (x - 3) = 26$$

yielding $x = 7$.
 
  • #3
Euge said:
Hi RTCNTC,

It's important to write down what your variables represent. If $x$ represents Lee's age, then $x - 3$, not $(2x + 1) - 3$, represents the age of Lee's younger sister. The equation is then

$$x + (2x + 1) + (x - 3) = 26$$

yielding $x = 7$.

There is a typo in the application. Lee's younger sister is 3 years younger than him not the older sister. I also got x = 7. So, Lee is 7 years old.
 
  • #4
My interpretation of the original problem is that "Lee" is a girl and the sentence "Lee's younger sister is three years younger than she is." means that the younger sister is three years younger than Lee.[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[/FONT][/FONT][/FONT]
 
  • #5
HallsofIvy said:
My interpretation of the original problem is that "Lee" is a girl and the sentence "Lee's younger sister is three years younger than she is." means that the younger sister is three years younger than Lee.[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main])[/FONT][FONT=MathJax_Main]⊂[/FONT][FONT=MathJax_Math]R[/FONT][FONT=MathJax_Main]([/FONT][FONT=MathJax_Math]T[/FONT][FONT=MathJax_Main])[/FONT][/FONT][/FONT]
Well, the answer is x = 7.
 

1. How do you find someone's age?

The most common way to find someone's age is by asking them directly or looking at their government-issued identification such as a driver's license or passport. Another way is to ask a family member or friend who may know the person's age.

2. What if the person's age is unknown?

If the person's age is unknown, you can try to estimate their age based on their appearance, or you can try to find records such as birth certificates or census data to determine their age. If all else fails, you can always ask the person for an estimate.

3. Is it possible to determine someone's age with just their name?

No, it is not possible to determine someone's age with just their name. Age is not typically included in a person's name, and there can be many people with the same name but different ages. More information is needed to accurately determine someone's age.

4. Are there any scientific methods for finding someone's age?

Yes, there are some scientific methods that can be used to estimate someone's age, such as radiocarbon dating for organic materials or using bone density and X-rays to determine age in humans. However, these methods are not always accurate and can only provide an estimate.

5. Can you legally find someone's age without their consent?

In most cases, it is not legal to find someone's age without their consent. Age is considered personal information and is protected by privacy laws. It is important to respect someone's privacy and only obtain their age with their permission or through public records.

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