GATE Civil Engineering (CE) 2018 Shift 2 Solved Paper

The compression curve (void ratio, e vs. effective stress, ${\mathit{\sigma }}_{\mathit{v}}^{\prime })$ for a certain clayey soil is a straight line in a semi-logarithmic plot and it passes through the points $\left(\mathit{e}=1.2;{\mathit{\sigma }}_{\mathit{v}}^{\prime }=50\mathit{k}\mathit{P}\mathit{a}\right)$ and $\left(\mathit{e}=0.6;{\mathit{\sigma }}_{\mathit{v}}^{\prime }=800\mathit{k}\mathit{P}\mathit{a}\right)$. The compression index (up to two decimal places) of the soil is ___________