M1V1 = M2V2
(2.50)(100.0) = (0.550)V2
V2 = 455mL
From 100.0 mL of 2.50 M KBr, you can prepare 455 mL of 0.550 M solution.
Greetings!
The result is:
The new volume is: 
Rationale:
Because the temperature remains constant, we can apply Boyle's Law to solve this issue.
Boyle's Law stipulates that:

Where,
P is the gas's pressure.
V is the gas's volume.
According to the information provided:

Let's put the values into the equation:


Consequently, the new volume is: 
Wishing you a lovely day!