Let $X$ be the random variable denoting the number of girls that are born. Then $X$ has a binomial distribution on $n=125$ babies and probability of getting a girl $p=0.5$ . The probability we want is

$\mathbb P(X\ge60)=\displaystyle\sum_{x=60}^{125}\binom{125}x0.5^{125-x}0.5^x\approx0.704=70.4\%$

7 0

3 years ago

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There are 20 parrots at the animal sanctuary. Their population is increasing at a rate of 15% per year. There are also 24 snakes

worty [1.4K]

For the answer to the questions above,
A) Parrots are following a Geometric Progression of 15% increase.

20(1.15), 20(1.15)², 20(1.15)³,

Function = 20(1.15)^n Where n is at the end of year, n =1, 2, 3, ..

Snakes are increasing by 4.

28, 32, 36,....

Function = 24 + 4n n = number of end year, n =1, 2, 3,...

B) After 10 years: 
Parrot = 20(1.15)¹⁰ = 80.91115471

Snakes = 24 + 4(10) = 64

C) After what time they are the same: 
We use trial and error:

Test: n 20(1.15^n) (24 + 4n)
 1 23 28
 2 26.45 32
 3 30.41 36 
 4 34.98 40
 5 40.23 44
 6 46.26 48
 7 53.20 52
 8 61.18 56
 9 70.36 60

After year 7, the Parrots increases far more.
At year 7 they are roughly the same.

8 0

3 years ago

Marcy had 567 earmuffs in stock. If she can put 18 earmuffs on each shelf, about how many shelves does she need for all the earm

spin [16.1K]

567 / 18 = 31.5

But because she can't make half a shelf, the answer would be 32 shelves

5 0

3 years ago

Solve the systems of equations by the elimination method: -2x + 2y = 2 -4y - 2x = -22

bekas [8.4K]

Answer:

(3,4)

Step by step explanation:

7 0

3 years ago