Question

Daca elevii unei clase se aseaza cate 2 in banca atunci unul sta singur iar doua banci raman libere. Daca elevii se aseaza cate 3 in banca atunci raman 6 banci libere. Aflatii nr. bancilor din clasa

Answer 1

$x\to nr. \ de \ banci \\\\ 2(x-2)+1\to nr. de \ elevi \\ 3(x-6)\to nr. \ de \ elevi \\\\ 2(x-2)+1=3(x-6) \\\\ 2x-4+1=3x-18 \\\\ 2x-3=3x-18 \\\\ 2x-3x=-18+3 \\\\ -x=-15 \\\\ \boxed{x=15} \\\\ 2(15-2)+1= \\\\ = 2*13+1= \\\\ =26+1= \\\\ =\boxed{27 \ elevi}$