Question

Determinati numerele x,y,si z stiind ca x pe trei y pe 4 si zpe cincisi x plus y plus z =84

Answer 1

$\frac{x}{3} = \frac{y}{4} = \frac{z}{5} =k~(constanta~de~proportionalitate) \\ \\ x=3k;~y=4k;~z=5k; \\ \\ x+y+z=84 \\ \\ 3k+4k+5k=84 \\ \\ 12k=84 \\ \\ k=7 \\ \\ \\ x=3*7 \\ x=21 \\ \\ y=4*7 \\ y=28 \\ \\ z=5*7 \\ z=35$