Question

Suppose y varies directly as x, and y =16 when x=8. Find y when x=16

Answer 1

y varies directly as x, and y =16 when x=8. Find y when x=16
y is double x
so when x=16
y=16x2 which equals 32

Answer 2

For this case, since the variation is direct then we have a relation of the form:

`image`

Where,

k: proportionality constant

To find k we substitute the following data:

y = 16 when x = 8

We have then:

`image`

Clearing the value of k we have:

`image`

Then, the equation is:

`image`

Substituting the value of x = 16 we have:

`image`

Answer:

The value of y for x = 16 is:

`y = 32`