Question

Y is inversely proportional to x2. When y =10, x = 2, what is y
when x = 10?

Answer 1

`\frac25`

Explanation:

`y \propto (1)/(x^2) \implies y=(k)/(x^2) \ \ \ \textsf{where k is some constant}`

when y = 10 and x =2:

`\implies 10=(k)/(2^2)`

`\implies k=40`

Therefore,

`\implies y=(40)/(x^2)`

when x=10:

`\implies y=(40)/(10^2)=(40)/(100)=\frac25`