The easy part about this question is that it already gives you the equation to use. If you're trying to find the weight in g/cm^3, all you have to do is divide the weight in grams (g) by the volume in cubic centimeters (cm^3).
The problem already gives you the volume, so you just need to convert kilograms (kg) into grams (g).
Hint: "kilogram" means 1000 grams. There are 1,000 grams in each kilogram.
So find the weight of the object in grams, then divide that number by the volume in cm^3.