Question

Intr-o sala de clasa, daca stau 2 elevi intr-o banca ramane o banca libera. Daca ar sta un elev in banca, ar ramane 13 elevi in picioare. Cati elevi sunt?

Answer 1

notam e -nr elevilor

              b- nr bancilor

e=2(b-1)

e=1xb+13

2(b-1)=1xb+13

2xb-2=1xb+13

2xb-1xb=13+2

b=15

e=2(15-1)=2x14=28 (elevi)

sau e=1x15+13=28 (elevi)

R: 15 banci si 28 elevi