# If y varies inversely with the square of x, and x=5 when y=3, what is the equation?

The variation equation is ${x}^{2} \cdot y = 75$
 y prop 1 /x^2 or y = k * 1/x^2 or x^2 *y = k ; x=5 , y =3 :. k = 5^2 *3 =75 or x^2 *y = 75
Hence the equation is ${x}^{2} \cdot y = 75$ [Ans]