Hello, can anyone help please? :D

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|

Ron has 8 caps and 4 of his caps are blue. thes rest of his cap are red. how many of ron's caps are red

What is the point estimate for the number of cars sold per week for a sample consisting of the following weeks: 1, 3, 5, 7, 10, 13, 14, 17, 19, 21?