Question

Scrie nr 300 ca suma a 4 numere direct proportionale cu 2,3,4,6. *b)scrie nr 130 ca o suma de trei nr invers proportionale cu 2,3 si 4. Va rog mult imi trebuie urgent!! :)

Answer 1

a/2=k     a=2k
b/3=k     b=3k
c/4=k     c=4k
d/6=k     d=6k
a+b+c+d=2k+3k+4k+6k=300
15k=300
k=300/15=20
a=2x20 =40
b=3x20=60
c=4x2=80
d=6x20=120
verificare 40+60+80+120=300

b)    a : 1/2 =k    a = k/2
       b: 1/3 =k     b=k/3  
       c: 1/4=k      c=k/4
a+b+c= 130
k/2+k/3+k/4=130
6k+4k+3k=130*12
13k=1560
k= 120
a=120/2=60
b=120/3=40
c=120/4=30
verificare 60+40+30=130