Question 263344
You asked" How can I" 
You can hire someone to do it for you.
You can learn how to do it on your own.
or 
perimeter=70
Since you want to know the perimeter we are done.
But my guess is that you copied the problem incorrectly.
It is hard to get a correct answer with a wrong question.


L=5+2w
p=2L+2W
70=2*(5+2w)+2w
70=10+4w+2w
60=6w
10=w
L=25
length is 25 and width is 10