Answer: 5/9
Explanation:
In order to find the simplest form, you have to find a factor which both the top and bottom can be divided by. so in this case both 10 and 18 are divisible by 2 which is how I got 5/9. Then to make sure you have found the simplest form, you can check to make sure your answer cannot be divided any further. :)
Hope this helps :)