I tried this task too, but my result is wrong. I dont know why because our solution path seems similar.
5/6 of the back lawn is mowed. Means 1 /6B is not mowed.
The total lawn is 4 /3 lawn.
(1/6 B) / (4/3B) = 1/8 which is incorrect.
Thanks in advance for your help.
According to me.....
5/6 of the total lawn is mowed as per your solution
and the total lawn is 4/3 (as per your solution)
So the lawn left unmowed will be given by (Total - Lawn mowed) ----> 4/3 - 5/6 = 1/2
and then (1/2) / (4/3) = 3/8
I hope that is clear now.