(A) 75P2−75C2
75P2=73!75!
=75×74
=5550
75C2=2×175×74
=25550
=2775
75P2−75C2=5550−2775
=2775
(A) matches with (III)
(B) 5P5−10C3
5P5=5!
=5×4×3×2×1
=120
10C3=3×2×110×9×8
=6720
=120
5P5−10C3=120−120
=0
(B) matches with (IV)
(C) 16C13−8C3
Using 16C13=16C16−13=16C3:
16C3=3×2×116×15×14
=63360
=560
8C3=3×2×18×7×6
=6336
=56
16C13−8C3=560−56
=504
(C) matches with (I)
(D) nP4=360
n(n−1)(n−2)(n−3)=360
For n=6:
6×5×4×3=30×12
=360
Therefore n=6
(D) matches with (II)
Final Matching:
(A) → (III) = 2775
(B) → (IV) = 0
(C) → (I) = 504
(D) → (II) = 6