Amaterial will float on the surface of a liquid if the material has a density less than that of the liquid. given that the density of water is approximately 1.0 g/ml, will a block of material having a volume of 1.3 104 in3 and weighing 350 lb float or sink when placed in a reservoir of water?

We will first convert lb to grams and in³ to milliliters. 
350 lb : 2.205 = 158.75733 kg = 158,757.33 grams
1.3 · 10^4 in³ = 13,000 in³ = 13,000 · 0.016387064 = 213.031 liters 
213.031 liters · 1,000 = 213,031 milliliters
Density = m / V = 158,753.33 g / 213,031 ml = 0.7452 g/ ml
A block of material will float.