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Qn #583
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The value of $\sum ^n_{r=1}\frac{{{{}^nP}}_r}{r!}$ is:
A.
$$2^n$$
B.
$$1-2^{-n}$$
C.
$$2^n-1$$
D.
$$2^{2n}-1$$
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❓ Question: The value of $\sum ^n_{r=1}\frac{{{{}^nP}}_r}{r!}$... | TANCET Group Studies | Tancet Group Studies