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Calculati cantitatea de apa adaugata la o solutie de masa 250g si de comcentratie procentuala die 20% daca la final a scazut concentratia la 10%!

Răspuns :

C=md/ms*100=>md=20*250/100=50g

ms=md+mH2O=>mH2O=200g

C=md/ms*100=> 10=50/50+mH2O*100=>500+10mH2O=5000=>4500=10mH2O=>mH2O=450g

m adaugat =>450-200=250g H2O

Nu sunt sigur..