Final answer:
The maximum number of units numbered (491, 495, 497, 499) that may be counted toward the major is 25 units.
Step-by-step explanation:
The maximum number of units numbered (491, 495, 497, 499) that may be counted toward the major is 25 units. The units are odd numbers, and the maximum number of odd numbers that can be added together is equal to the largest odd number. In this case, 499 is the largest odd number, so the maximum number of units that can be counted is 499.