4. The following letters are rearranged BROWN. What is the probability that the BRO are together and in this order

Answer 1

You have 5! ways to rearrange BROWN

If BRO together and in this order, you have 3! ways

so the probability is =3!/5!=1/20

Answer 2

You could either have:

BROxx

xBROx

xxBRO

where xx are the letters W or N in any order.

Probability getting BROxx

Get a B: 1/5

Then get an R: 1/4

Then get an O: 1/3

Get BRO = 1/5*1/4*1/3 = 1/60

Probability getting xBROx

Get x (W or N) = 2/5

Get a B = 1/4

Get an R = 1/3

Get an O = 1/2

Get BRO = 2/5*1/4*1/3*1/2=1/60

Probability getting xxBRO

Get x (W or N) = 2/5

Get x (W or N) = 1/4

Get B = 1/3

Get R = 1/2

Get O = 1

Get BRO = 2/5 * 1/4 * 1/3 * 1/2 * 1 = 1/60

Probability get BRO = 1/60 + 1/60 + 1/60 = 3/60 = 1/20