Question

A coin is tossed three time then find the probablity of the following events: 

A is an event of getting a head on middle coin.

B is an event of getting exactly one tail. 

Answer 1

A coin is tossed 3 times.

∴ Sample space S = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}

n(S) = 8

Let A = Event of getting head on middle coin

A = {HHH, HHT, THH, THT}

n(A) = 4

P(A) = `"n(a)"/"n(S)" = 4/8 = 1/2`

P(A) = `1/2`

Let B = Event of getting exactly one tail

B = {HHT, HTH, THH}

n(B) = 3

P(B) = `"n(B)"/"n(S)" = 3/8` 

P(B) = `3/8`