Answer: Section A holds 27500 , Section B has 14100 and SEction C has 13400.
Explanation:
Let x= Number of seats in section A.
y = Number of seats in section B.
z= NUmber of seats in sectionC.
As per given , we have
x+y+z=55000 (i)
x= y+z (ii)
28x+16y+12z=1156400 (iii)
Substitute value of x from (ii) in (i), we get

From (i)

From (iii), we get

Multiply 3 to (iv), we get

Eliminate (v) from (iv), we get

from (iv)

Hence, Section A holds 27500 , Section B has 14100 and SEction C has 13400.