Can someone help me on my last question? I’ll appreciate you a lot!! I’ll also post it here

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|

What three-dimensional solid have 6 rectangular faces, 2 equal bases that are not rectangles and 18 edges