If 6Pr = 360 and If 6Cr = 15, find r ?
A. 5
B. 6
C. 4
D. 3
Answer: Option C
Solution (By Examveda Team)
nPr = nCr × r! 6Pr = 15 × r! 360 = 15 × r! r! = $$\frac{{360}}{{15}}$$ = 24 r! = 4 × 3 × 2 × 1 ⇒ r! = 4! Therefore, r = 4This Question Belongs to Arithmetic Ability >> Permutation And Combination
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