Question

If `y` varies directly with `x` and `y=15` when `x=5`, what is the value of `k`?

Answer 1

`k=3`

Explanation:

`"the initial statement is "ypropx`

`"to convert to an equation multiply by k the constant"`
`"of variation"`

`rArry=kx`

`"to find k use the given condition"`

`y=15" when "x=5`

`y=kxrArrk=y/x=15/5=3`

`"the direct variation equation is "y=3x`

Answer 2

The answer is `3`.

Explanation:

`y\propto x\implies y=kx`

For the given values, `15=5k\implies k=\frac 15 5=3`.