
Spencer H. answered 06/15/20
Engineer Grad and Experienced Tutor for Math and Science Tutoring
Hello!
To solve this we simply look at the number of possibilities for each letter and multiply them together.
To find the number of three call letters we have to consider three letters:
The first letter can only be K or W, so it has 2 options.
The second and third letters can be any letter in the alphabet so they EACH have 26 options.
To find the total number of options we multiply the number of options for each letter:
2 * 26 * 26 = 1352
Adding a fourth letter means another letter with 26 options. We can take our previous value and simply multiply by 26.
1352 * 26 = 35152