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JEE MATHEMATICS MCQ: PERMUTATIONS

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Application +4 | -1

There are

p

letters

a, q

letters

b, r

letters

c

. The number of ways of selecting

k

letters out of these if

p < k < q < r

is

View answer and explanation

Correct option: B

\frac{1}{2}(p+1)(2 k-p)

Option B (

\frac{1}{2}(p+1)(2 k-p)

) is correct because it represents the number of ways of selecting k letters out of p 'a's, q 'b's, and r 'c's, given p < k < q < r.

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