Question

Daca numerele a, b si c sunt direct proportionale cu numerele 3, 4 si 5, iar suma lor este egala cu 36, care sunt aceste numere?

Answer 1

Răspuns:

Salutare !

{ a , b , c } direct proportional cu { 3 , 4 , 5 }

a + b + c = 36

a/3 = b/4 = c/5 = K

a = K3

b =K4

c = K5

K12 = 36

K = 3

a = 3 x 3 = 9

b = 3 x 4 = 12

c = 3 x 5 = 15

Succes !

#Albert1001

Answer 2

$\it a+b+c=36\ \ \ \ \ (*)\\ \\ \{a,\ b,\ c\}\ d.\ p.\ \{3,\ 4,\ 5\} \Rightarrow \dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{5}=\dfrac{a+b+c}{3+4+5}\ \stackrel{(*)}{=}\ \dfrac{36}{12}=3 \Rightarrow\\ \\ \\ \Rightarrow\ \begin{cases}\it \dfrac{a}{3}=3 \Rightarrow a=3\cdot3=9\\ \\ \it \dfrac{b}{4}=3 \Rightarrow b=4\cdot3=12\\ \\ \it \dfrac{c}{5}=3 \Rightarrow c=5\cdot3=15\end{cases}$