If `a` denotes the number of permutations of `(x+2)` things taken all at a time, `b` the number of permutations of `x` things taken `11` at a time and `c` the number of permutations of `x-11` things taken all at a time such that `a=182b c ,` find the value of `xdot`
a) 10
b) 12
c) 15
d) 18

Options

A. 15
B. 12
C. 10
D. 18

Answer

B

Explanation

`because a=182bc`
`implies(x+2)!=182xx.^(x)P_(11)xx(x-11)!`
`implies(x+2)!=182xx x!`
`implies(x+2)(x+1)=14xx13` ,brgt `impliesx+1=13`
`thereforex=12`