A mini license plate for a toy car must consist of three numbers followed by a letter. Each number must be a 3,6, or 9. Each letter must be a T or R. Repition of digits is Not permitted.
a. Use the counting principle to determine the number of points in the sample space.
b. Construct a tree diagram to represent this situation.
c. List the sample space.
d. Determine the exact probability of creating a mini license with a T. Give solution exactly in reduced fraction form.