Explanation:
out of the 3 values, there is for every line one missing. so, we need to use the formula that calculates the missing value out of the other 2.
and based on the density value (in most cases already given in the table) we mark float or sink (as your paper says, if it is smaller than 1g/cm³, it will float, if it is larger, it will sink).
1.
density is missing
D = M/V = 12/0.5 = 12/0.5 × 2/2 = 24/1 = 24 g/cm³
sinks
2.
volume is missing.
V = M/D = 16/0.2 = 80 cm³
floats
3.
mass is missing.
M = D×V = 5×20 = 100 g
sinks
4.
volume is missing.
V = M/D = 0.9/0.3 = 3 cm³
floats
5.
density is missing
D = M/V = 6/4 = 3/2 × 0.5/0.5 = 1.5/1 = 1.5 g/cm³
sinks
6.
density is missing
D = M/V = 8/1.8 = 4.444444444... g/cm³
sinks
7.
mass is missing.
M = D×V = 9×13 = 117 g
sinks
8.
density is missing
D = M/V = 14.7/15 = 0.98 g/cm³
floats
9.
mass is missing.
M = D×V = 2×1.1 = 2.2 g
sinks
10.
volume is missing.
V = M/D = 17/3 = 5.66666666... cm³
sinks