A sample of gas occupies 26.5 L under a pressure of 1.3 atm. What would the resulting volume be if the pressure were increased to 3.9 atm if the temperature did not change?

The equation for this problem would be P₁V₁=P₂V₂, where the P's are your initial and final pressures in atm and your V's are the initial and final volumes in L. Plug in 26.5 for V₁, 1.3 for P₁, and 3.9 for P₂:

26.5 (1.3) = 3.9V₂

3.9V₂=34.45

V₂=8.8 L