Question

after a bride has interviewed 7 djs to play at her wedding, her fiance tells her she needs to narrow it down to 2 djs. in how many ways can she rank the 2 djs? a) 14 b) 21 c) 2 d) 5,040 e) 42 f) none of the above.

Answer 1

Using permutation, the number of ways she can rank the 2 DJs is 42.

A permutation of a set is, broadly speaking, a rearranging of its elements if the set is already ordered, or arranging its members into a sequence or linear order.

The bride interviewed 7 DJs to play at her wedding.

She asks her fiance to select 2 DJs using permutation.

ₙPₐ = n! / ( n - a )!

P( 7, 2 ) = 7!/( 7 - 2 )!

P( 7, 2 ) = 7!/5!

P( 7, 2 ) = (7 × 6 × 5 × 4 × 3 × 2) / (5 × 4 × 3 × 2)

P( 7, 2 ) = 7 × 6

P( 7, 2 ) = 42

The number of ways in which she ranks the 2 DJs is 42.

The correct option is (e) 42 ways.

Learn more about permutation here:

brainly.com/question/1216161

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