Question

Harry tosses a coin 4 times.The probability that he gets at least as many heads as tails is __

Answer 1

Given

The coin is tossed 4 times

The number of possible outcomes when a coin is tossed 4 times can be found using the formula:

`=\text{ 2}^n`

Hence,

`\begin{gathered} =\text{ 2}^4 \\ =\text{ 16} \end{gathered}`

The probability, P that Harry gets as many heads as tails can be calculated using the formula:

`P\text{ = }\frac{Number\text{ of required outcomes}}{Total\text{ number of possible outcomes}}`

The outcomes for tossing the coin 4 times includes:

HHHH, 0 tails and 4 heads,

HHHT, 1 tails and 3 heads,

HHTH, 1 tails and 3 heads

HHTT, 2 tails and 2 heads

HTHH, 1 tails and 3 heads

HTHT, 2 tails and 2 heads

HTTH, 2 tails and 2 heads

HTTT, 3 tails and 1 heads

THHH, 1 tails and 3 heads

THHT, 2 tails and 2 heads

THTH, 2 tails and 2 heads

THTT, 3 tails and 1 heads

TTHH, 2 tails and 2 heads

TTHT, 3 tails and 1 heads

TTTH, 3 tails and 1 heads

TTTT, 4 tails and 0 heads

Of these, eleven outcomes have the number of heads equal to or greater than the number of tails. So the probability of getting at least as many heads as tails is:

`P\text{ = }(11)/(16)`

Answer:

`P=(11)/(16)`