Hint on scuba diver

Using the ideal gas law formula

PV=nRT

Given that P1 * V1 = n1 * R * T1 is the first situation

Given that P2 * V2 = n2 * R * T2 is the second situation

We can derive P1 * V1 / T1 = n1 * R

We can derive P2 * V2 / T2 = n2 * R

Since in this situation n1 = n2

And R is the same constant for both equations

Therefore

P1 * V1 / T1 = P2 * V2 / T2

Since the unknown is V2 convert equation to

P1 * V1 * T2 / T1 * P2 = V2

Substitute your values and solve

But make sure each value is in the same units

For instance pressure should be in the same units

And temperature should be in the same units

And volume should be in the same units

Regards,

Bill

PS - Who was that guy Ideal anyway