Question

1.Sa se calculeze media aritmetica a 3 numere, stiind ca unul dintre ele este 14,2 , iar media aritmetica a celorlalte este 18,25
2. a) x*1,5*2,7+4,05*x=10,53

Answer 1

$\bold{1.} \ M_a= \frac{x+y+z}{3}; \\ x=14,2; \ \ \frac{y+z}{2}=18,25, \ \Rightarrow y+z=18,25 \cdot 2= 36,5; \\ \Rightarrow M_a= \frac{14,2+36,5}{3} = \frac{50,7}{3} =\boxed{16,9}. \\ \bold{2.} \ x \cdot 1,5 \cdot 2,7+4,05 \cdot x=10,53 \\ x \cdot 4,05+4,05 \cdot x=10,53 \\ x \cdot (4,05+4,05)=10,53 \\ x \cdot 8,1=10,53 \\ x= \frac{10,53}{8,1} \\ \Rightarrow \boxed{x= 1,3}.$