diketahui x:y=5:3, sedangkan y:z=4:5. jika 2( x+y+z) =94, nilai dari 3y adalah...?

x = 5
y    3
3x = 5y
x = 5y
       3
y = 4
z    5
5y = 4z
z = 5y
       4

2(x+y+z)= 94
2((5y/3)+y+(5y/4))=94  {kedua ruas dikalikan 12}
2 (20y+12y+15y) = 1128
2 (47y) = 1128
47y = 564
y = 12

3y
= 3(12)
= 36