For the given figure, considering Pratt's model of isostatic compensation at the crust–mantle boundary, the crustal density ($\rho_1$) that explains 1.5 km deep lake is $\underline{\hspace{1cm}}$ kg/m$^3$. (Consider density of water $\rho_w = 1000$ kg/m$^3$) [round off to 2 decimal places]
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