Help would be appreciated :)

I'm pretty sure the answer is 8, because when r = 25 and x = 5, you have to divide r by 5 to get x. This way, because 40/5 is 8, I think that would be the answer you're looking for.

So x = 8.

x and r are directly proportional means we can write;  x = k*r where k is a constant.

To find k use the fact that x = 5 when r = 25, so   5 = k*25 .  You should be able to find k from this.

Then use that to find x when r is 40:  x = k*40

If x and r are directly proportional and x = 5 when r = 25, then what is x when r = 40?

x : r = 5 : 25

5 : 25 = x : 40

x = (5 * 40) / 25

x = 8