60;3>a:2 de 4 ori
60:3:4=a:2
20:4=a:2
5=a:2
a=2*5
a=10
verificare
60:3>10:2 de 4 ori
20>5 de 4 ori........=> 20=5*4
b) 5t+1c=55 lei - (minus)
3t+1c=41 lei
----------------------------------
=2t+ 0c =14 lei
2t=14
t=14:2
t=7 lei costa o tarta
3*7lei+1c=41lei
21lei+1c=41lei
1c=41-21
1c=20lei costa un cozonac
verificare
3*7lei+1*20lei=
=21lei+20lei
=41lei
5*7lei+1*20lei=
=35lei+20lei
=55lei