Răspuns :
g+p=30 (p=30-g)
15g+20p=500
15g+20(30-g)=500
15g+600-20g=500
600-500=20g-15g
100=5g
100:5=g
20=g
20 duble de grau a cumparat
15g+20p=500
15g+20(30-g)=500
15g+600-20g=500
600-500=20g-15g
100=5g
100:5=g
20=g
20 duble de grau a cumparat
a-duble grau,b-duble porumb
a+b=30
15a+20b=500
a=30-b
15(30-b)+20b=500
450-15b+20b=500
5b=50
b=10
a=20
a+b=30
15a+20b=500
a=30-b
15(30-b)+20b=500
450-15b+20b=500
5b=50
b=10
a=20