Final answer:
The total number of possible locker code combinations with one letter from four choices and two numbers from two choices without repetition is 8.
Step-by-step explanation:
The student's question involves calculating the number of possible combinations for a locker code that must contain one letter (from the options a, b, c, and d) and two numbers (5 and 6) without repetition. To find the total number of possible combinations, we use the multiplication principle.
For the letter, there are 4 choices (a, b, c, d). Since no repetition is allowed, after choosing a letter, there will be only 1 choice left for the second number after choosing the first. Therefore, we have 4 options for the letter, 2 options for the first number, and 1 option for the second number.
The total number of combinations for the locker code is therefore 4 letters × 2 numbers × 1 number, which equals 8 possible combinations.