Datele problemei:
II+III+IV= 1000 = III+788
IV=3xII
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Rezolvare:
Cati copaci au plantat elevii de clasa a IIIa?
1000 = III-788
scris invers sa fie mai usor : III+788=1000
1000-788=212 copaci
Din:
II+III+IV= 1000
II+212+IV=1000
II+IV=1000-212
II+IV=788
Stim ca IV=3xII
=>
II+3xII=788
4xII=788
Cati copaci au plantat elevii de clasa a IIA?
788:4=197
Dar cei de clasa a IV?
197x3=591
Verificare: 591+197+212=1000