question_answer

The value of n if

a.	\[{}^{n+4}{{C}_{n+1}}-{}^{n+3}{{C}_{n}}=15\left( n+2 \right)\]	(p)	6
b.	\[11({}^{n}{{P}_{4}})=20({}^{n-2}{{P}_{4}})\]	(q)	18
c.	\[{}^{2n}{{C}_{3}}=11{}^{n}{{C}_{3}}\]	(r)	16
d.	If p(n,r) = 1680  and C(n,r) = 70	(s)	27

A)  a\[\to \]p, b\[\to \]q, c\[\to \]r, d\[\to \]s

B)  a\[\to \]r, b\[\to \]p, c\[\to \]s, d\[\to \]q

C)  a\[\to \]s, b\[\to \]c, c\[\to \]q, d\[\to \]p

D)  a\[\to \]s, b\[\to \]r, c\[\to \]p, d\[\to \]q

E)  None of these