Density of saturated KBr
According to “Aqueous Solubility of Inorganic Compounds at Various Temperatures”, in CRC Handbook of Chemistry and Physics, 90th Edition (CD-ROM Version 2010), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL., the solubility (expressed as mass fraction) of potassium bromide $(\ce{KBr})$ in water is $39.4\ \%$ (at $T = 20\ \mathrm{^\circ C}$) and $40.4\ \%$ (at $T = 25\ \mathrm{^\circ C}$).

According to “Concentrative Properties of Aqueous Solutions: Density, Refractive Index, Freezing Point Depression, and Viscosity”, in CRC Handbook of Chemistry and Physics, 90th Edition (CD-ROM Version 2010), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL., the properties of a potassium bromide solution of with a mass fraction of $w_{\ce{KBr}} = 40.0\ \%$ at $T = 20\ \mathrm{^\circ C}$ are as follows.


molality: $b_{\ce{KBr}} = 5.602\ \mathrm{mol\ kg^{-1}}$
concentration: $c_{\ce{KBr}} = 4.620\ \mathrm{mol\ l^{-1}}$
density: $\rho = 1.3746\ \mathrm{g\ cm^{-3}}$