👤

determinati numerele x,y,z invers proportionale cu numerele 2,5 si 20, iar x+y+z=60

Răspuns :

Notam
x·2=y·5=z·20=k
x=k/2
y=k/5
z=k/20
x+y+z=60 inlocuim:
k/2+k/5+k/20=60 ⇒ aducem la acelas numitor
10k+4k+k=20·60 ⇒
15k=1200 ⇒k=1200:15⇒k=80

x=80/2=40
y=80/5=16
z=80/20=4
x/1/2=y/1/5=z/1/20=k
k constanta
x=k/2
y=k/5
z=k/20
x+y+z=60
k/2+k/5+k/20=60
numitor comun 20
10k+4k+k=1200
15k=1200
k=1200:15
k=80
x=80/2
x=40
y=80/5
y=16
z=80/20
z=4
verif:40+16+4=60