Question

A coin is biased such that a is times as likely to occur as a tail. Find the expected number of when this coin is tossed twice.

Answer 1

Complete question:

A coin is biased such that a head is three times as likely to occur as a tail. Find the expected number of tails when this coin is tossed twice.

Answer:

1/2

Step-by-step explanation:

Head is 3 times as likely to occur as tail;

Hence,

Sample space for 2 tosses :

{HH, HH, HH, HH, HH, HH, HH, HH, HH, HT, HT, HT, HT, HT, HT, TT}

Expected probability (E(x)) = Σx*p(x)

P(x) = required outcome / Total possible outcomes

x : __________ 0 ______ 1 _______ 2

p(x) : ________9/16_____6/16_____1/16

Σx*p(x) : 0(9/16) + 1(6/16) + 2(1/16)

= 0 + 6/16 + 2/16

= 0 + 3/8 + 1/8

= 4/8

= 1/2