Akeep tossing a fair coin, until he get 2 consecutive heads, define x to be the number of tosses for this process; b keep tossing another fair coin, until he get 3 consecutive heads, define y to be the number of the tosses for this process.

Step-by-step explanation:

I think you're making an incorrect assumption here. X and Y are two events based on two separate, independent series of coin tosses, from coins A and B, respectively. Here's an example:

Coin one:

T-T-T-T-H-H

Coin two:

H-H-H-T-T-T

Event X (two heads in a row from coin A) occurred after event Y (three heads in a row from coin B). In the language of the question, X=6 and Y = 3. Since X>Y is a possible event in the space, P{X>Y} must be greater than zero.

The problem can be broken down by the outcome of the first toss of the two coins.

Bearing arithmetic typos, the answer should be 43/58.

thanx

hope it helps youuu

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

i would say c is the best answer, hope it's right!

good luck! =)

cutie~