In how many ways can 4 married couples attending a concert be seated in a row of 8 seats if: a) there are no restrictions? b) each married couple is seated together?

a) 40,320

b) 384

Step-by-step explanation:

Given,

The total number of seats = 8,

Also, these 8 seats are occupied by 4 married couples or 8 people,

a) Thus, if there is no restrictions of seating ( that is any person can seat with any person ),

Then, the total number of arrangement = 8 ! = 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1

= 40320,

b) if each married couple is seated together,

Then, the 4 couples can seat in 4 pair of seats,

Also, in a pair of seats a couple can choose any of the two seats,

So, the total number of arrangement

geometric series converge the common ratio r has magnitude less than one.

which is equivalent to

for the example we need

|2-x| < 1

-1 < 2-x   and 2-x < 1

x < 3 and x > 1

we can write that

answer: 1 < x < 3

1a. common ratio r=250/25=10 > 1     diverges

1b.   r=50/100=1/2 converges

when these converge they converge to

where a is the first term.

answer: 200

1c. r=-1   so it's not the case that |r| < 1.     diverges

2a. x is the common ratio so we converge when |x|< 1

2b.   r=-10x / -2 = 5x.

we converge when

|5x| < 1

|x| < 1/5

2c.   r=3-2x

-1 < 3-2x and 3-2x < 1

-4 < -2x and 2 < 2x

x < 2 and 1 < x

1 < x < 2

2d. [/tex] r=-48x^3/12 = 4x^3[/tex]

|4x^3| < 1

|x^3| < \frac 1 4

|x| < 4^{-1/3}