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Question
Out of given 7 consonants and 3 vowels, how many words can be formed that contain 3 consonants and 2 vowels or 3 vowels and 2 consonants?
A
15120.
B
15130.
C
15110.
D
15140.
Soln.
Ans: a
Ans: a
We can make the selection in 3C3 × 7C2 + 3C2 × 7C3 ways. But the five members can themselves be arranged in 5! ways. So the number of words is 120 × (3C3 × 7C2 + 3C2 × 7C3) = 15120.