Giving brainless to the correct answer!

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.

What is the domain of the step function f(x)=[2x]-1?

Math ! will give branliest at a car and truck dealership, the probability that a vehicle is white is 0.25 . the probability that it is a pick up truck is 0.15 . the or obability that it is a white pick up truck is 0.06 . what is the probability that the vehicle is white, given that the vehicle is a pickup truck . round your answer to two decimal places .