Question

What is `y` when `x=10`, if `y=8` when `x=20`?

Answer 1

When `x = 10, color(blue)(y = 4`

Explanation:

Method 1:
As per the data provided:
When `color(blue)(x=20 , y = 8`

So when the value of `x` is halved, `x = 20 /2, color(blue)(x = 10`

The value of `y` is also halved `= 8/2 , color(blue)(y= 4`

Method 2

When `color(blue)(x=20 , y = 8`

The value of `y` is `0.4` times `x`.

`y = 0.4 xx color(blue)(20 = 8`

So, when `x = 10`

`y = 0.4xx 10`

`color(blue)(y = 4`