Question

daca nr x y z sunt invers proportionale cu 0,2 0,5 0,(3) , iar xyz=15360, atunci suma nr. x y z este:

Answer 1

0,2=2/10=1/5;  0,5=5/10=1/2;  0,3=3/9=1/3

{a,b,c} i.p.{1/5; 1/2; 1/3}

a/5=b/2=c/3=k

a=5k; b=2k; c=3k

a·b·c=5k·2k·3k=30k^3=15360

=> k^3=512=8^3

k=8 => a=5·8=40;  b=2·8=16;  c=3·8=24

a+b+c=40+16+24=80

R: a) 80