Question

Media artimetica a trei fractii zecimale este 15,(6).Prima fractie zecimala se mareste cu 1,(6) iar a doua cat si a treia se micsoreaza cu 0,8(3) , Calculati media artimetica a fractiilor zecimale dupa aceste modificari.

Answer 1

notam cu a, b, c cele 3 fractii
ma=$\frac{a+b+c}{3} =15,(6)= \frac{156-15}{9} = \frac{141}{9} = \frac{47}{3 } \\ a+1,(6) +b-0,8(3)+c-0,8(3)= a+b+c+ \frac{16-1}{9} - \frac{83-8}{90} -\frac{83-8}{90} \\ dar \\ a+b+c=\frac{47}{3 }*3=47 \\3* ma=47+ \frac{15}{9} - 2*\frac{75}{9} =47+ \frac{5}{3} -2* \frac{25}{3} \\ =47- \frac{45}{3} =47-15=32 \\ deci \\ ma= \frac{32}{3} =10,(6)$