.
ANSWER. (6*5*4*3) * (10*9).
Explanation.
6 options for the letters in the 1-st position.
5 options for the 5 remaining letters in the 2-nd position.
4 options for the 4 remaining letters in the 3-rd position.
3 options for the 3 remaining letters in the 4-th position.
10 options for the digits in the 5-th position.
9 options for the 9 remaining digits in the 6-th position.
It gives the answer.
You compute the number.
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To see many similar solved problems, look into the lessons
- Combinatoric problems for entities other than permutations and combinations
- Miscellaneous problems on permutations, combinations and other combinatoric entities
in this site.
After reading these lessons, you will be trained in solution such problems and will get more confidence.
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Combinatorics: Combinations and permutations".
Save the link to this textbook together with its description
Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson
into your archive and use when it is needed.