I know I’m doing something wrong but I’m not sure what it is

One of the inventors of integrated circuits observed that the number of transistors that fit on an integrated circuit will double every 24 months. what type of relationship most appropriately models this situation?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days