Math and Arithmetic
Statistics
Algebra

# How many different 3 letter combinations are there... for example airports are typically LHR LGW LAX etc how many different possible combinations are there?

91011 ###### 2010-02-19 16:12:57

There are 26 letters in the alphabet.

If letters may be repeated in the airport code, then there are (26 x 26 x 26) = 17,576 possibilities.

If adjacent letters can't be duplicates, then there are (26 x 25 x 25) = 16,250 possibilities.

If all three letters must be different, then there are (26 x 25 x 24) = 15,600 possibilities.

🦃
0
🤨
0
😮
0
😂
0

## Related Questions  If order doesn't matter, 15 combinations and if order does matter, 360 combinations are possible. If you are allowed to repeat letters (A-Z) then there are 17,576 different combinations. If you can not repeat letters then there are 15,600 combinations.  Since a number can have infinitely many digits, there are infinitely many possible combinations.    If the numbers can be repeated and the numbers are 0-9 then there are 1000 different combinations.   18 different combinations. When a coin is tossed twice there are four possible outcomes, (H,H), (H,T), (T,H) and (T,T) considering the order in which they appear (first or second). But if we are talking of combinations of the two individual events, then the order in which they come out is not considered. So for this case the number of combinations is three: (H,H), (H,T) and (T,T). For the case of tossing a die once there are six possible events. The number of different combinations when tossing a coin twice and a die once is: 3x6 = 18 different combinations. there are 1,929,770,126,028,800 different colour combinations possible on a Rubik cube.  want total answer possible of different sudoku 9 x 9 total amount only The number of combinations - not to be confused with the number of permutations - is 2*21 = 42. There are 362880 possible spare combinations in 10 pin bowling. 4 gametes are possible: DGw Dgw dGw dgw are all the possible combinations  There are 84 different combinations possible for the committee of 6, taken from4 students and 5 teachers.1.- The committee with 4 students has 4C4 number of combinations of 4 students out of 4 and 5C2 number of combinations of 2 teachers out of 5 to be combined with. The product of these two give the number of different combinations possible in a committee formed by 4 students and 2 teachers.2.- The committee with 3 students has 4C3 number of combinations of 3 students out of 4 and 5C3 number of combinations of 3 teachers out of 5 to be combined with. The product of these two give the number of different combinations possible in a committee formed by 3 students and 6 teachers.3.- The committee with 2 students has 4C2 number of combinations of 2 studentsout of 4 and 5C4 number of combinations of 4 teachers out of 5 to be combined with. The product of these two give the number of different combinations possible in a committee formed by 2 students and 4 teachers.4.- The committee with 1 student has 4C1 number of combinations of 1 student out of 4 students and 5C5 number of combinations of 5 teachers out of 5 to be combined with. The product of these two give the number of different combinations possible in a committee formed by 1 student and 5 teachers.We now add up all possible combinations:4C4&acirc;&circ;&trade;5C2 + 4C3&acirc;&circ;&trade;5C3 + 4C2&acirc;&circ;&trade;5C4 + 4C1&acirc;&circ;&trade;5C5 = 1(10) + 4(10) +6(5) + 4(1) = 84There are 84 different combinations possible for the committee of 6, taken from4 students and 5 teachers.[ nCr = n!/(r!(n-r)!) ][ n! = n(n-1)(n-2)&acirc;&circ;&trade;&acirc;&circ;&trade;&acirc;&circ;&trade;(3)(2)(1) ]  Assuming each "digit" actually has 10 different states, there are one million combinations possible in a six-digit combination lock. However, many combination lock designs actually have fewer than 10 different states per "digit", resulting in far fewer actual combinations on such locks. There are 8 possible combinations:{},{2},{6},{8},{2,6},{2,8},{6,8} and{2,6,8}There are 8 possible combinations:{},{2},{6},{8},{2,6},{2,8},{6,8} and{2,6,8}There are 8 possible combinations:{},{2},{6},{8},{2,6},{2,8},{6,8} and{2,6,8}There are 8 possible combinations:{},{2},{6},{8},{2,6},{2,8},{6,8} and{2,6,8}  There are many different combinations of amino acids and proteins and peptide bonds.

###### Math and ArithmeticAlgebraBiologyHuman Anatomy and PhysiologyGeneticsRestaurants and Dining EstablishmentsRubik's CubesSudokuBowlingProbabilityStatisticsLocks and Latches Copyright © 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.