Question

Media aritmetica a tri numere este egala cu 16. Aflati numerele stiind ca ele sunt direc proportionale cu numerele 4,5, 7​

Answer 1

notam nr cu a,b,c

media aritmetica:

$\frac{a + b + c}{3} = 16 \\ a + b + c = 16 \times 3 \\ a + b + c = 48$

{a,b,c} d.p. {4,5,7}

$\frac{a}{4} = \frac{b}{5} = \frac{c}{7} = k$

k-coeficient de proportionalitate

$\frac{a}{4 } = k = > a = 4k$

$\frac{b}{5} = k = > b = 5k$

$\frac{c}{7} = k = > c = 7k$

a+b+c=48

4k+5k+7k=48

16k=48

k=48:16

k=3

a=4k=>a=4×3=>a=12

b=5k=>b=5×3=>b=15

c=7k=>c=7×3=>c=21