3.
a)Diana:250g+1000g+500g=1750g
Alexandru:200g+300g=500 g
b)1750g+500g=2250 g cantaresc cumparaturile impreuna
c)1750g-500g=1250 g cantareste mai mult o plasa decat cealalta
4.
a-prima magazie
b-a doua magazie
a+b=45
a=4b
5b=45
b=45:5
b=9 t a doua magazie
a=9x4
a=36 t prima magazie