Question

what amount of ammonium chloride that will separate out when 55g of its solution at 373k is cooled to 273k(solubility at 373k -55g and at 273k - 37g)

Answer 1

If the solubility at 373 is 55 g then all of it will be dissolved. At 273, it will dissolve 37 g.
So 55-37 = ? will crystallize.