Solve for the unknown variable 28.3=2(3.14)r

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 equation expression the relationship between the number of boxes b and the number of cans c and the proportion is 48

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?