Question

raportul dintre numerele a si b este egal cu 2/5,iar media lor aritmetica este 35 aflati numerele a si b
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Answer 1

$\it m_a=\dfrac{a+b}{2}=35\Rightarrow a+b=70\ \ \ \ \ (1)\\ \\ \\ \dfrac{a}{b}=\dfrac{2}{5} \Rightarrow \dfrac{a+b}{b}=\dfrac{5+2}{5}\ \stackrel{(1)}{\Longrightarrow}\ \dfrac{70}{b}=\dfrac{^{10)}7}{\ 5} \Rightarrow \dfrac{70}{b}=\dfrac{70}{50} \Rightarrow b=50\ \ \ \ (2)\\ \\ \\(1),\ (2) \Rightarrow a+50=70 \Rightarrow a=20$

Numerele cerute sunt: a=20,  b=50

Answer 2

(a+b)/2=35

a+b=2×35

a+b=70

a/b=2/5

a=2k

b=5k

2k+5k=70

7k=70

k=70:7

k=10

a=2×10

a=20

b=5×10

b=50