Solving a problem in chemistry section 11 point 46

Solving a problem in chemistry section 11 point 46

46. Saturated aqueous solution of calcium bromide 80 g 20 g anhydrous salt. The resulting mixture was heated until complete dissolution of salts, then cooled to the initial temperature. As a result, the cooling dropped 41.5 g of crystalline residue. What is the formula of crystalline, if it is known that the saturated solution contains 58.7% anhydrous salt?

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Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)