The relationship between γ_sat, γ_d, γ and S is ______
a) γ = γ_d*S[γ_sat-γ_d]
b) γ = \(\frac{γ_d}{S[γ_{sat}-γ_d]}\)
c) γ = γ_d+S[γ_sat-γ_d]
d) γ = γ_d-S[γ_sat-γ_d]

Answer: c
Explanation: The bulk unit weight is given by,
\(γ = \frac{(G+eS) γ_w}{(1+e)} \,or\, γ = G\frac{γ_w}{(1+e)} + S\frac{eγ_w}{(1+e)}\)
\(γ = γ_d+S[\frac{(G+e) γ_w}{(1+e)} – \frac{G γ_w}{(1+e)}]\)
γ = γ_d+S[γ_sat-γ_d].