Answer:
98,706,816 combinations
Step-by-step explanation:
Let's make a little graphic of it:
Letters (4): ___ ___ ___ ___
Numbers (3): ___ ___ ___
In the 4 lines/placeholders of the letters, it can be ANY letter of the alphabet, it can be any 26 of them.
In the 3 lines of the numbers, it can be any number from 0 - 5, which is 6 numbers.
Thus we can say:
Letters = 26 * 26 * 26 * 26 = 456,976
Numbers = 6 * 6 * 6 = 216
Their PRODUCT is the number of combinations possible.
456,976 * 216 = 98,706,816 combinations