Question

COROANA !!!!
Ajutorrrrrrrr!!!!!! VREAU SI EU REZOLVAREA PROBLEMEI: INTR-O SCOALA SUNT 940 ELEVI. DACA PLECA 10 BAIETI SI VIN 3 FETE , ATUNCI NR. FETELOR AR FI DE 2 ORI
MAI MARE DECAT NR. BAIETILOR. CATI BAIETI SI CATE FETE INV. IN ACEA SCOALA?????? DAU COROANA!!!!!!

Answer 1

$f+b=940 \\\\ 2(b-10)=f+3 \\\\ 2b-20=f+3 \\\\ f=2b-20-3 \\\\ f\to 2b-23 \\\\\\ 2b-23+b=940 \\\\ 3b=940+23 \\\\ 3b=963 \ \ \ |:3 \\\\ \boxed{b=321 \ baieti} \\\\\\ f=2*321-23 \\\\ f=642-23 \\\\ \boxed{f=619 \ fete}$

Answer 2

f+b=940;
⇒3+f=2[b-10]
⇒3+f=2b-20
⇒2b=3+f+20
⇒2b=23+f⇒b=[23+f]/2;
⇒f+[23+f]/2=940
⇒2f+23+f/2=940
⇒3f+23=2·940
⇒3f+23=1880
⇒3f=1880-23
⇒3f=1857
⇒f=1857/3
⇒f=619[fete];
⇒b=[23+619]/2
⇒b=642/2
⇒b=321[baieti];