Question

Suma a3nr. este790. Aflati numerele stiind ca sunt invers proportionale cu 3,5,8

Answer 1

{a,b,c} i.p.(invers proportionale) {3,5,8}

⇒3a=5b=8c=k

3a=k⇒a=k/3

5b=k⇒b=k/5

8c=k⇒c=k/8

dar a+b+c=790

deci k/3+k/5+k/8=790

aducem la acelasi numitor

40k+24k+15k=790×3×5×8

79k=79×10×3×5×8

k=150×8

k=1200

dar a=k/3=1200/3=400⇒  a=400
b=k/5=1200/5=240⇒        b=240
b=k/8=1200/8=150⇒        c=150

Verificare
a+b+c=790

400+240+150=790
790=790