P(Blue)=0.5, P(Red)=0.4, P(Purple)=0.1

This is unconditional probability as the events do not affect each other.

P(blue, red, purple once) =(0.5)(0.4)(0.1)=0.02

That is to say:

Blue, Red, Purple = 0.02.

Blue, Purple, Red = 0.02

Red, Blue, Purple = 0.02

Red, Purple, Blue = 0.02

Purple, Blue, Red = 0.02

Purple, Red, Blue = 0.02

So what is the probability of you receiving a purple, blue and red in any order?