Question

daca elevii clasei se aseaza cate unul in banca, raman 13 elevi in picioare,iar daca se aseaza cate doi elevi intr-o banca raman doua banci libere.cati elevi si cate banci erau?

Answer 1

notam e = elevi
b= banci

e=b+13

e =2×(b-2)

2×(b-2)=b+13

2×b-4=b+13

2×b-b=13+4

b= 17 (banci)
_________

e = 2×(17-2)

e = 2×15

e = 30 (elevi )
__________