Work is calculated as P*(V2 - V1). In this problem, we have a constant P = 2.52 x 10^5 Pa, an initial volume V1 = 1.1 x 10^-4 m^3, and a final volume V2 = 1.50 x 10^-3 m^3.
Substituting:
P*(V2 - V1)
= (2.52 x 10^5 Pa)(1.50 x 10^-3 - 1.1 x 10^-4) m^3
= 350.28 Pa-m^3
= 350.28 J
So the gas in the balloon does 350.28 J of work on its surroundings.