Question

Doi frati au impreuna 21 de ani . Varsta unuia este $\frac{3}{4}$ din varsta celuilalt . Sa se afle varsta fiecaruia

Answer 1

[tex]A+B=21~ani \\ \\ A= \frac{3B}{4} \\ \\ \frac{3B}{4}+^{4)}B=^{4)}21 \\ \\ \frac{7B}{4}= \frac{84}{4} \\ \\ 7B=84 \\ \\ \boxed{B=12~ani} \\ \\ A=21-12 \\ \\ \boxed{A=9~ani} [/tex]