Let's analyze Part A first. We know the following:
- Let \( x \) represent the amount of money Sammie had before going to the mall.
- She spent half of her money at the mall, which means she spent \( \frac{1}{2}x \).
- After spending that money, she received $50 from her uncle.
- She came home with $90.
Putting this together, we can write the equation based on her situation:
- After spending half of her money, she had \( x - \frac{1}{2}x = \frac{1}{2}x \).
- Then, she received $50, so the amount she came home with is \( \frac{1}{2}x + 50 \).
- This amount equals $90.
So we can write the equation:
\[ \frac{1}{2}x + 50 = 90 \]
Thus, the correct equation from the options you provided is:
D: \( \frac{1}{2} x + 50 = 90 \)
Now, let's solve Part B to determine how much money Sammie had when she went to the mall.
From the equation we found in Part A:
\[ \frac{1}{2}x + 50 = 90 \]
To isolate \( x \), first subtract 50 from both sides:
\[ \frac{1}{2}x = 90 - 50 \] \[ \frac{1}{2}x = 40 \]
Next, multiply both sides by 2 to solve for \( x \):
\[ x = 40 \times 2 \] \[ x = 80 \]
Therefore, Sammie had $80 when she went to the mall.