Let's break down the information given in the problem:
- Let X represent Lisa's sister's age.
- Since Lisa is 4 years younger than her sister, Lisa's age can be represented as \( X - 4 \).
Now we want to find the expression for the sum of Lisa’s age and her sister’s age, which can be given as:
\[ \text{Lisa's age} + \text{Sister's age} = (X - 4) + X \]
Calculating that:
\[ (X - 4) + X = 2X - 4 \]
Now let's examine the expressions provided:
- \( X - (X - 4) \): Simplifying this gives \( X - X + 4 = 4 \), which does not represent the sum of their ages.
- None of these: We'll see if any of the other options are correct before choosing this.
- \( (X + 4) - X \): Simplifying this gives \( X + 4 - X = 4 \), which also does not represent the sum of their ages.
After reviewing the options, none of the provided expressions represent the correct sum of Lisa's age and her sister's age. Therefore, the answer is:
None of these.
1 answer