3 unbekante and 2 gleichungen

Question

Aufgabe:

a mal b mal c = 480      a :3= b :4= c  :5

Answer 1

a*b*c= 480

a/3= b/4=c/5

a= (3/4)b

c= (5/4)b

(3/4)b*b*(5/4)b= 480

(15/16)b^3 = 480

b^3 = 512

b=8

a=6

c=10

Answer 2

Hallo,

a/3= c/5

5a=3c

a= (3/5) c

b/4=c/5

5b= 4c

b=(4/5) c

--->
a bc =480

(3/5) c * (4/5) c *c= 480

(12/25) c^3= 480 |*25

12 c^3 = 480 *25 =12000

c^3= 1000

c= 10

b=8

a=6