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VA ROOG! Prin introducerea a X grame sare de bucatarie in 900g solutie de concentratie 10%, se obtine o noua solutie cu concentratia 14,5%. Ce valoare are X? Multumesc!

Răspuns :

c = md*100/ms
md1 = 10*900/100 = 90 g sare
md2 = md1 + x = 90+x
ms2 = ms1 + x = 900+x
14,5 = (90+x)*100/(900+x)
9000+100x = 13050+14,5x
85,5x = 4050
x = 47,36 g sare