BITSAT2010MathematicsBinomial TheoremActual
With 17 consonants and 5 vowels the number of words of four letters that can be formed having two different vowels in the middle and one consonant, repeated or different at each end is
Options
- A5780
- B2890
- C5440
- D2720
Correct answer
A. 5780
Step-by-step solution
The two letters, the first and the last of the four lettered word can be chosen in ((17)^2 ) ways, as repetition is allowed for consonants. The two vowels in the middle are distinct so that the number of ways of filling up the two places is ( ^5 P ₂=20 ). The no. of different words (=(17)^2 20=5780 ).