Question

Suppose that y is inversely proportional to the square root of x, and that y=45 when x=64. What

is y when x=25?

Answer 1

y is 28.125 when x = 25

Solution:

Given that,

y is inversely proportional to the square root of x

Therefore,

`y \propto √(x)\\\\y = c √(x)` ----------- eqn 1

Where, c is constant of propotionality

y = 45 when x = 64

Substitute in eqn 1

`45 = c * √(64)\\\\45 = c * 8\\\\c = 5.625`

What is y when x = 25?

Substitute x = 25 and c = 5.625 in eqn 1

`y = 5.625 * √(25)\\\\y = 5.625 * 5\\\\y = 28.125`

Thus y is 28.125 when x = 25