Răspuns:
ro=m/v---> m,apa= 1g/mlx2000ml=200g
masa totala= 2000g apa+20g zahar+ 200gsare= 2220g
2220g amestec....2000g apa....20g zahar,....200g sare
100.................................x............................y.........................z
x=100x2000/.2220=..90% apa........................
y= 20x100/2220=..........................
z= 200x100/2220=...........finalizeaza calculele, trebuie ca x+y+z=100 !!!
Explicație: