Question

A man writes letters to one of two newspapers: the Argus and the Beacon. If a newspaper publishes one of his letters he sends the next one to the same newspaper; if not, he tries the other newspaper next time. The probablility that the Argus published one of his letters is 0.6 whereas for the Beacon it is 0.75. If he tosses a fair coin to decide where to send his first letter, calculate the probability that the third letter is send to Argus and his fourth letter send to Beacon.

Can you help me with starting the tree diagram please

Answer 1

His first letter can be sent to A (0.5) or B (0.5). Do we consider that too at the beginning of tree diagram

Answer 2

yes

Answer 3

I don't quite understand what is meant by ' If a newspaper publishes one of his letters he will send next one to same newspaper if not tries the other one next time'

Answer 4

it will take me a few minutes to make sense of it.

Answer 5

can u check my tree diagram plz ill draw it now

Answer 6

ok. AP means A published and AP' means A does not publish
if A is published, then you send the next letter (letter #2) to A
if AP' then you send letter #2 to B

Answer 7

it is a confusing tree because we have to keep track of where we send the next letter, and whether it was published.

Answer 8

if AP then next letter gets sent to A . is the prob for that 1?

Answer 9

I am tempted to write it this way