Question

Suma a trei numere este 75.Afla numerele,stiind ca sunt direct proportionale cu 3,5,7

Answer 1

a+b+c=75

a,b,c    dp cu 3,5,7

a/3= b/5= c/7=k
a=3k
b=5k
c=7k

3k+7k+5k=75
15k=75

k=5

a=3*5=15
b=5*5=25
c=7*5=35

Answer 2

{a,b,c} direct prop cu {3,5,7}⇒ $\frac{a}{3}$=$\frac{b}{5}$=$\frac{c}{7}$=k
⇒ a=3k, b=5k, c=7k
a+b+c=75 ⇒ 3k+5k+7k=75⇒ 15k=75⇒k=75:15=5⇒
a=3*5=15
b=5*5=25
c=7*5=35