Question

Suma numerelor x si y este 20 si multimea {x;y} este invers proportionala cu {0,25, 0,(3)}. Determinati numerele

Answer 1

0,25=25/100=1/4
0,(3)=3/9=1/3
x+y=20
{x,y} ip {1/4,1/3}
x/4=y/3=k
x=4k
y=3k
inlocuim in relatia x+y=20
4k+3k=20
7k=20
k=20/7
x=4k=4·20/7=80/7
x=80/7
y=3k=3·20/7=60/7

verificare
80/7+60/7=20
140/7=20
20=20