Let the height of the kiwi be x, then the height of the ostrich is 20 + 4x.
20 + 4x = 108
4x = 108 - 20 = 88
x = 88/4 = 22
The height of the kiwi is 22 inches.
The difference between 1/2 and 1/6 is 2/6. So to write an expression we could do x divided by 2/6=2/3. So instead of a division expression, we could make that into a multiplication problem 2/6 times 2/3=x. 2/6 times 2/3= 4/18 so your answer is 4/18 or 2/9