S2 Continuous Uniform Distribution

Hey guys,

Need help on part c method.

What have you done for part (a)? Part (c) depends on part (a).

I've drew the continuous uniform distribution diagram for part a.



I just don't understand why it's P (8 <= X <= 12).

Thanks

It could be that the part with the mark on is the shorter bit, which is why you need x>=8. Or it could be that the other bit is the shorter one. It has to be greater than or equal to 8. Taking that from 20 gives the bit with the mark on being no more than 12.