Question

Impartiti nr90 in parti invers proportionale cu 1/3 ,1/5 si 1/7

Answer 1

a·1/3=b·1/5=c·1/7=k
⇒a·1/3=k⇒a=k/1/3⇒a=k·3⇒a=3k;
⇒b·1/5=k⇒b=k/1/5⇒b=k·5⇒b=5k;
⇒c·1/7=k⇒c=k/1/7⇒c=k·7⇒c=7k;
⇒a+b+c=90
⇒3k+5k+7k=90
⇒15k=90
⇒k=90/15
⇒k=6;
⇒a=3·6=18;
⇒b=5·6=30;
⇒c=7·6=42;