Answer:
Height of the bottom seats is 2 meter.
Step-by-step explanation:
It has been given in the question seats are located on a slope having gradient 
We have to find the height h of the bottom seats.
Since gradient = 
Therefore, from the figure attached,


12 - h = 
12 - h = 10
h = 12 - 10
h = 2 m
Therefore, height of the bottom seats if 2 m.