Question

Find y when x equals 10 if y equals eight what x equals 20

Answer 1

There can be 2 answers depending the proportionality between y and x
Assuming y is directly proportional to x

`y=kx` where k is constant of proportionality

`8=20k`

`k=(8)/(20)=(2)/(5)<span>`

`y=(2)/(5)x`

`y=(2)/(5)*10`

`y=4`

Assuming y is indirectly proportional to x

`y=(k)/(x)` where k is constant of proportionality

`8=(k)/(20)`

`k=160`

`y=(160)/(x)`

`y=(160)/(10)`

`y=16`