Question

Given that y is directly proportional to x. If y = 30 and x= 5, write an equation that connects y with x.

Answer 1

Given:

y is directly proportional to x.

`y=30` when
`x=5`

To find:

The equation that connects y with x.

Solution:

It is given that, y is directly proportional to x. So,

`y\propto x`

`y=kx` ...(i)

Where, k is the constant of proportionality.

We have,
`y=30` when
`x=5`. Substituting these values in (i), we get

`30=k(5)`

Divide both sides by 5.

`(30)/(5)=k`

`6=k`

Substituting
`k=6` in (i), we get

`y=6x`

Therefore, the required equation is
`y=6x`.