For this case we have that if "y" varies directly with "x", then it is true that:
[tex]y = kx[/tex]
Where:
k: It is the constant of proportionality
We have according to the data that:
[tex]10 = k (3)[/tex]
We find the value of "k":
[tex]k = \frac {10} {3}[/tex]
Having "k", we find "y" when [tex]x = 6[/tex]:
[tex]y = \frac {10} {3} (6)\\y = \frac {60} {3}\\y = 20[/tex]
ANswer:
[tex]k = \frac {10} {3}\\y = 20[/tex]
