Question

Determinati numerele a,b si c invers proportionale cu numere 2; 4 si 5 daca suma lor este egala cu a) 19; b) 57; c) 76.

Answer 1

{a, b, c} ip {2; 4; 5}
a*2=b*4=c*5=k
a*2=k=> a=k/2
b*4=k=>b=k/4
c*5=k=>c=k/5
k/2+k/4+k/5=19
10k+5k+4k=19*20
19k=380=> k=380/19
k=20=> a=20/2=>a=10
             b=20/4=> b=5
             c=20/5=>c=4
asemanator, b si c