A mini license plate for a toy car must consist of a letter followed by two numbers. Each letter must be a C, A or R. Each number must be a 3 or 7. Repetition of digits is permitted.
a) Use the counting principle to determine the number of points in the sample space.
b) Describe how a tree diagram would represent this situation.
c) List the sample space.
d) Determine the exact probability of creating a mini license plate with a 7. Give solution exactly in reduced fraction form.