Question

A unbiased coin is tossed 5 times. find the probability of getting 2 tails.

Answer 1

Answer:

20

Step-by-step explanation:

Answer solved in permutation

5p4=5!/(5-2)!

=20

Answer 2

Answer:

When an unbiased coin is tossed 5 times then the probability of getting 2 tails is 10/32.

Step-by-step explanation:

A coin is tossed 5 times.

When a coin is tossed then the total number of possible outcomes is given by $n^{2}$.

Therefore, when 5 coins are tossed then the total number of possible outcomes is $2^{5}$ i.e. 32.

Therefore, possible outcomes are,

HHHTT, TTTHH, HHTTH, TTHHT, HHTHT, TTHTH, HTHTH, THTHT

HTHHT, THTTH, HHHHT, HTTHH, THHTT, TTTTH, HHHTH, TTHHH

HHTTT, TTTHT, HHTHH, THHHT, HTTTH, TTHTT, HTHHH, THTHH

HTHTT, THTTT, HHHHH, THHHH, THHTH, HTTHT, HTTTT, TTTTT

Total number of outcomes containing two tails is 10.

Therefore,

P(E) = Getting two tails

P(E) = 10

P(n) = 32

$P(E)=\frac{Probability \ of \ 2 \ tails }{Total \ number \ possible \ outcomes} \\\\P(E)=\frac{10}{32}$

Therefore, the probability of getting 2 tails is 10/32.