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If 56P r + 6 : 54P r + 3 = 30800 : 1 then the value of r is?

Correct Answer: 41

Explanation:

56Pr + 6 : 54Pr + 3 = 30800 : 1
⇒ 56! / (50 - r)! = (30800 x 54!) / (51-r!)
⇒ 56 x 55 = 30800/(51 - r)
⇒ 51 - r = 10
∴ r = 41


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