Petrol / water densities

Petrol density=800kg\m3 Water density = 1000kg/m3 
Q)a) which has more mass 1 m3 of petrol or 1 m3 of petrol
b)which has more volume 1 kg of petrol or 1 kg of water
Q)2) how to claculate volume with density and mass?
Category:Physics quizes