Question

IF y varies directly as x , and y is 6 when x is 72, what is the value of y when x is 8

Answer 1

y=kx, k is not equal to 0
when y=6, x=72, 6=72k
k=1/12
so y=1/12*x
when x=8, y=1/12*8=2/3

Answer 2

`y=(2)/(3)`

Explanation:

It has been given that y varies directly as x

Thus, we have

y = kx, where k is constant of proportionality.

Now, y = 6, x = 72.

Substituting these values in above equation and find k

`6=72k`

Divide both sides by 72

`k=(6)/(72)\\\\k=(1)/(12)`

Now, we have to find y when x = 8

`y=(1)/(12)*8\\\\y=(2)/(3)`

Therefore, the value of y is
`(2)/(3)`