Which expression can be used to find the area of a circle with a diameter of 80 cm?

. Let X and Y be random variables of possible percent returns (0%, 10%,

bazaltina [42]

(a) The marginal distribution of X is

Pr(X = x) = ∑ Pr(X = x, Y = y)

… = 0.0625 + 0.0625 + 0.0625 + 0.0625

… = 0.25

That is, the first equality follows from the law of total probability, with the sum taken over y from {0, 5, 10, 15}. Each probability Pr(X = x, Y = y) is given in the table to be 0.0625.

Similarly, the marginal distribution of Y is

Pr(Y = y) = 0.25

(b) Yes, they're independent because

Pr(X = x, Y = y) = 0.0625,

and

Pr(X = x) Pr(Y = y) = 0.25 • 0.25 = 0.0625.

(c) The mean of X is

E[X] = ∑ x Pr(X = x)

… = 0.25 ∑ x

… = 0.25 (0 + 5 + 10 + 15)

… = 7.5

and you would find the same mean for Y,

E[Y] = 7.5

The variance of X is

V[X] = E[X^2] - E[X]^2

… = (∑ x^2 Pr(X = x)) - 7.5^2

… = 0.25 (∑ x^2) - 56.25

… = 0.25 (0^2 + 5^2 + 10^2 + 15^2) - 56.25

… = 31.25

and similarly,

V[Y] = 31.25

(each sum is taken with x and y from {0, 5, 10, 15})

7 0

3 years ago

A bicycle store costs $3500 per month to operate. The store pays an average of $75 per bike. The average selling price of each

vfiekz [6]

Answer: the store needs to sell 50 bicycles each month to break even

Step-by-step explanation:

The average selling price of each bicycle is $145.

When we talk of break even, we are referring to the point at which the income being accrued from a business is equal to the total cost of running the business. At this point, their is no profit and there is no loss.

From the example information given,

Total cost of running the business will be

cost of operating the bicycle store + the total amount the store pays per bike.

cost of operating the bicycle store

= $3500 per month

The store pays an average of $75 per bicycle. If the store buys x bicycles per month, then,

Total the total amount the store pays per bike = 75 × x = 75x

Total cost of running the business per month

= 3500 + 75x - - - - - - -1

The average selling price of each bicycle is $145. This means that the selling price for x bicycles will be

145 × x = 145x

Therefore , total income is $145x

To break even,

145x = 3500 + 75x

145x - 75x = 3500

70x = 3500

x = 3500 / 70 = 50

8 0

2 years ago

Simplify 1/3 + 4/x-2 = 6

Maurinko [17]

Answer:

1/3+4/x-2=6

Step-by-step explanation:

your is answer 6

4 0

1 year ago

HELP Dieing from math in the picture. I think I did it wrong. Please help. :(

nikdorinn [45]

X = 352.3 [your work is correct]

then the perimeter would be 352.3 + 352.3 + 280 + 280 = 1,264.55

4 0

1 year ago

in a class of 34 students 19 of them are girls what percentage of the class are girls to 1 decimal place

motikmotik

Answer:

55.9% of the class are girls

Step-by-step explanation:

19/34 = 0.559

0.559 x 100 = 55.9%

6 0

2 years ago

Read 2 more answers