Question

If y varies directly as x and y = 49 when x = 7, what is the value of y when x = 3?

Answer 1

y=21 because 3/21=7 and 7*3=21 so Y=21 

Answer 2

Direct variation:

`y=kx`

y=49 when x=7.

`49=7k \\ k=(49)/(7) \\ k=7`

y=? when x=3.

`y=7 * 3 \\ y=21`

y=21 when x=3.