Question

If y varies inversely with the square of x, and y = 26 when x = 4, find y when x = 2.

A. 13
B. 52
C. 208
D. 104

Answer 1

D; 104

This is the correct answer

Answer 2

D. 104

Explanation:

`y \: \alpha \: \frac{1}{ {x}^(2) } \\ \\ y = \frac{k}{ {x}^(2) }`

when y is 26, x is 4:

`26 = \frac{k}{ {(4)}^(2) } \\ k = 416`

when x is 2:

`y = \frac{416}{ {x}^(2) } \\ \\ y = \frac{416}{ {(2)}^(2) } \\ y = 104`