Please Help with density!

[kmkindig]

A 100 cm^3 container has 4 g of an ideal gas in it at 250 kPa. If the volume is changed to 50 cm^3 and the temperature remains constant, what is the new density in kg/m^3.

Any help would be greatly appreciated to help me understand! Thanks

[mgb_phys]

Density is mass/volume
What have you changed, what stays the same?

[djeitnstine]

PV=nRT