Assume the radius is R.
2*pi*R = 28 -> R = 14/pi
So the area will be pi*R^2 = 196/pi
Tossing a coin is a binomial experiment.
Now lets say there are 'n' repeated trials to get heads. Each of the trials can result in either a head or a tail.
All of these trials are independent since the result of one trial does not affect the result of the next trial.
Now, for 'n' repeated trials the total number of successes is given by

where 'r' denotes the number of successful results.
In our case
and
,
Substituting the values we get,


Therefore, there are 1352078 ways to get heads if a person tosses a coin 23 times.
Answer:
Step-by-step explanation:
9a + 5b + 5c = 9
Multiplying the whole equation by -2.
-18a - 10b - 10c = -18.
Hence, the answer is -18.