Tìm a, b, c biết:

a) $\frac{a}{2} = \frac{b}{1} = \frac{c}{3} = \frac{a + b + c}{2 + 1 + 3} = \frac{48}{6} = 8$

Suy ra a = 16; b = 8; c = 24.

b) $\frac{a}{2} = \frac{b}{3}; \frac{b}{2} = \frac{c}{3}$ do đó $\frac{b}{3} = \frac{2 c}{9} = \frac{c}{4.5}$

Suy ra $\frac{a}{2} = \frac{b}{3} = \frac{c}{4.5} = \frac{a + c}{6.5} = \frac{26}{6.5} = 4$

Vậy a = 8; b = 12; c = 18