Answer:
28
Step-by-step explanatiIn order to solve this problem we need to find out what $QR$ is. 
We know that the perimeter of the parallelogram was given as $24$ and that two of the sides were given as $5$. $5+5=10$ $24-10=14/2=7$. Now we know that the base was $7$. 
We can find the height by taking the area that they gave us and dividing that by $7$. We get $4$. 
 
Since we now know that the height of the parallelogram is $4$ that means $OQ$ is also $4$. 
 
Next we need to find what $RT$ is. 
$4^2+B^2=5^2$. 
Since we now $5^2$ is $25$ and that $4^2$ is $16$, we can use the following equation. 
$25-16=9$. $\sqrt{9}=3$. 
Now we know that $RT$ is $3$ we can start adding the sides. 
 
$7+3=10+4=14 \cdot 2=28$. 
 
[b]The perimeter of the rectangle $QOST$ is 28![/b]