Aballoon at an amusement park has 1,500 g of gas. by what amount will the mass of the balloon decrease if all the gas inside it escapes? - 750 g - 1,500 g -2,000 g - 3,000 g someone me it will be s apprecaited!

The answer is best explained in the diagram below.

Let m =  the mass of the balloon material (g).

At state 1, the total mass of the balloon is the mass of the balloon material and the mass of gas.
The total mass in state 1 is
m₁ =(m + 1500) g

At state 2, 1500 g of gas has escaped. Only the mass of the balloon material remains.
The total mass in state 2 is
m₂ = m g.

The decrease in mass of the balloon is
m₁ - m₂ = (m + 1500) - m = 1500 g

1,500 g