Question

Aflati numerele x y z stiind ca sunt direct proportionale cu 3 7 si 11 si x+2y +3z=200

Answer 1

x / 3 = y / 7 = z / 11 = k ⇒ x = 3 k ;   y = 7 k;   z = 11 k 

x + 2 y + 3 z = 200 

3 k + 2 × 7 k + 3 × 11 k = 200 

3 k + 14 k + 33 k = 200 

50 k = 200 ⇒ k = 200 : 50 ⇒ k = 4 

x = 3 × 4 = 12 

y = 7 × 4 = 28 

z = 11 × 4 = 44 

Verific:   12 + 2 × 28 + 3 × 44 = 12 + 56 + 132 = 200