You have to use the equation P₁V₁=P₂V₂ for the first 2 questions and V₁/T₁=V₂/T₂ for the third one.
1) Since you have to find the final volume you have to solve the equation above for V₂ to get V₂=P₁V₁/P₂
P₁=1atm
V₁=2.00L
P₂=6x10^4atm
when you plug everything in you should get 3.33x10^-5 L
2) You are again trying to find V₂ so use the equation V₂=P₁V₁/P₂
P₁=1.2atm
V₁=15000L
P₂=250atm
when you plug everything in you should get 72L
3) we are trying to find the final volume so use the equation V₂=V₁T₂/T₁
V₁=2.2L
T₁=14.2°C (convert this into 287.2K since most gas law equations require the use of kelvin)
T₂=38.98°C (tern this to 311.98K for the same reason as above)
when you plug everything in you should get 2.39L
I hope this helps. Let me know in the comments if anything if anything is unclear.