Hello There!
I'm not sure how to explain how i got the answer.
I basically trial and used trial and error.
It is 10 and 20
To test it follow through:
10 x 20 = 200
20 + 20 + 10 + 10 = 60
The length is 20 and the width is 10.
Hope This Helps You!
Good Luck :)
- Hannah ❤