Question

daca se aseaza cate 2 elevi in banca,raman 6 elevi fara loc,iar daca se aseaza cate 5,raman 6 banci libere.
cati elevi sunt in clasa si cate banci?​

Answer 1

Răspuns:   30 elevi si 12 banci

Explicație pas cu pas:

Notez numarul bancilor cu ,,b"

Datele problemei

2 × b + 6 → cate 2 elevi in banca, raman 6 elevi in picioare

5 × ( b - 6 ) → cate 5 elevi in banca, raman 6 banci libere

_______________________________________

5 × ( b - 6 ) = 2 × b + 6 → elevi

5 × b - 30 = 2 × b + 6

5 × b - 2 × b = 6 + 30

3 × b = 36

b = 36 : 3       ⇒   b = 12 ( banci )

2 × 12 + 6 = 24 + 6 = 30 ( elevi )

__________________________

Verific: 5 × ( 12 - 6 ) = 5 × 6 = 30 elevi

Answer 2

2×b+6(daca se aseaza cate 2 in banca raman 6 elevi fara loc)

5×(b-6)(cate 5 elevi,raman 6 banci libere)

Cele două relatii sunt egale,astfel:

2×b+6=5×(b-6)

2b+6=5×b-30

2b=5b=30+6

5b-2b=3b

36:3b=12

2×12+6=24+6=30