Answer:
x = 10
Step-by-step explanation:
Direct variation:
In direct variation, if one variable increase or decrease, the other variable also increases or decrease in the same way.
[tex]\sf \dfrac{x}{y}=k\\\\\\x = ky[/tex]
When x = 7 & y = 21, k will be,
[tex]\sf k = \dfrac{x}{y}\\\\\\ = \dfrac{7}{21}\\\\k = \dfrac{1}{3}[/tex]
Now, we have to find the value of x, when y = 30
[tex]\sf x = 30*\dfrac{1}{3}\\\\\\x = 10[/tex]
