Let \( x \) represent the height of Karen's older sister in inches. According to the problem, half of her older sister's height plus 27 inches equals Karen's height:
\[ \frac{x}{2} + 27 = 59 \]
To solve for \( x \), first, subtract 27 from both sides:
\[ \frac{x}{2} = 59 - 27 \] \[ \frac{x}{2} = 32 \]
Now, multiply both sides by 2 to solve for \( x \):
\[ x = 32 \times 2 \] \[ x = 64 \]
Therefore, Karen's older sister is 64 inches tall.