Help me asap (please please)

Mathematics

1 answer:

CaHeK987 [17]3 years ago

4 0

Area of a circle = pi*r^2.

Here, A = 380.13 mi. Unfortunately, "mi" is NOT a unit of area.

So I will assume that the problem should read A = 380.13 sq. miles.
380.12 mi^2
Thus, 380.13 mi^2 = 3.14*r^2, and r^2 = ------------------- 121.057 mi^2
3.14

The radius is the sqrt of 121.057 mi^2: 11.00 miles.

The diam. is twice that, or d = 22.00 miles.

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A coin, having probability p of landing heads, is continually flipped until at least one head and one tail have been flipped. (a

Natali [406]

Answer:

(a)

The probability that you stop at the fifth flip would be

$p^4 (1-p) + (1-p)^4 p$

(b)

The expected numbers of flips needed would be

$\sum\limits_{n=1}^{\infty} n p(1-p)^{n-1} = 1/p$

Therefore, suppose that $p = 0.5$ , then the expected number of flips needed would be 1/0.5 = 2.

Step-by-step explanation:

(a)

Case 1

Imagine that you throw your coin and you get only heads, then you would stop when you get the first tail. So the probability that you stop at the fifth flip would be

$p^4 (1-p)$

Case 2

Imagine that you throw your coin and you get only tails, then you would stop when you get the first head. So the probability that you stop at the fifth flip would be

$(1-p)^4p$