Răspuns: 33 elevi si 23 banci
Explicație pas cu pas:
Notez numar banci cu ,,b"
Datele problemei:
2 × ( b - 1 - 6 ) + 1 → elevi: cate 2 elevi in banca, un elev sta singur si 6 banci raman goale
3 × ( b - 12 ) → elevi: cate 3 elevi in banca, raman 12 banci libere
______________________________________________________
3 × ( b - 12 ) = 2 × ( b - 7 ) + 1 ⇒ elevi
3 × b - 36 = 2 × b - 14 + 1
3 × b - 2 × b = - 13 + 36
b = 23 ( banci )
3 × ( 23 - 12 ) = 3 × 11 = 33 elevi
