Question

If `y` varies inversely with `x`, and if `y=10` when `x=1.2`, what is the value of `x` when `y=30`?

Answer 1

`x=0.4`

Explanation:

The formula of inverse proportion is `y=k/x`, where `k` is a constant.

When `y=10` and `x=1.2`,

`10=k/1.2`
`k=10xx1.2`
`color(white)(k)=12`

When `k=12` and `y=30`,

`30=12/x`
`x=12/30`
`color(white)(x)=0.4`

Hence, when `y=30`, `x=0.4`.