Answer:
=x7+9
Step-by-step explanation:
if 540 is 90% or 0.9 then 0.1 or 10% is 1/9 of 540.
540/9 is 1/9 of 540, and 10% of the school's population. that makes 60
so 540 + 60 = 100% of the school assembly.
600 students
9
hope this helps :)