Do not understand how to get the grades percent

Only do question 15 50 points Topic: Percentage

Varvara68 [4.7K]

Answer:

see below

Step-by-step explanation:

The total number of trees is

567+324+156+89+678 =1814

Percent fir = 567/1814 = .312568908=31.26 %

Percent pine = 324/1814 = .178610805=17.86%

Percent larch = 156/1814 =.085997795=8.60%

percent cedar = 89/1814 =.049062845=4.91%

Percent hemlock = 678/1814 = .373759647=37.38%

The total should be 100 %

31.26+17.86+8.60+4.91+37.38=100.01 ( rounding error because we rounded to the hundredths place)

4 0

3 years ago

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A company has to buy computers and printers. Each computer, x, costs $585 and each printer, y, costs $385. If the company spends

Luden [163]

The company bought 9 computers and 6 printers

Solution:

Let "x" be the number of computers bought

Let "y" be the number of printers bought

cost of 1 computer = $ 585

cost of 1 printer = $ 385

The company buys a total of 15 machines

Therefore, we can frame a equation as:

number of computers bought + number of printers bought = 15

x + y = 15 ------ eqn 1

The company spends $7,575

Therefore, we can frame a equation as:

number of computers bought x cost of 1 computer + number of printers bought x cost of 1 printer = 7575

$x \times 585 + y \times 385 = 7575$

585x + 385y = 7575 ------ eqn 1

Let us solve eqn 1 and eqn 2

From eqn 1,

x = 15 - y --------- eqn 3

Substitute eqn 3 in eqn 2

585(15 - y) + 385y = 7575

8775 - 585y + 385y = 7575

-200y = 7575 - 8775

-200y = -1200

y = 6

Substitute y = 6 in eqn 3

x = 15 - 6

x = 9

Thus the company bought 9 computers and 6 printers

6 0

3 years ago

Rosa & her friends are eating out for dinner. The bill was $45.80. They want to leave a 20% tip. How much should they leave

Ksenya-84 [330]

The tip should be $9.16

6 0

3 years ago

When an automobile is stopped with a roving safety patrol,each tire is checked for tire wear, and each headlight is checkedto se

ryzh [129]

Answer:

a) Joint ptobability distribution

$\begin{pmatrix} &Y=0&Y=1&Y=2&Y=3&Y=4\\X=0&0.3&0.05&0.025&0.025&0.1\\ X=1&0.18&0.03&0.015&0.015&0.06 \\ X=2&0.12&0.02&0.01&0.01&0.04\end{pmatrix}$

b) P(X<= 1 and Y <= 1) = P(X<= 1) * P(Y<=1) = 0.56

c) P(X + Y = 0)=0.3

d) P(X + Y <= 1)=0.53

Step-by-step explanation:

We have to construct the joint probability table with the marginal probabilities of X and Y.

X can take values from 0 to 2, and Y can take values from 0 to 4.

We can calculate each point of the joint probability as:

$P(x,y)=P_x(x)*P_y(y)$

Then, the joint probabilities are:

X=0 Y=0 Px=0.5 Px=0.6 P(0,0)=0.3

X=0 Y=1 Px=0.5 Px=0.1 P(0,1)=0.05

X=0 Y=2 Px=0.5 Px=0.05 P(0,2)=0.025

X=0 Y=3 Px=0.5 Px=0.05 P(0,3)=0.025

X=0 Y=4 Px=0.5 Px=0.2 P(0,4)=0.1

X=1 Y=0 Px=0.3 Px=0.6 P(1,0)=0.18

X=1 Y=1 Px=0.3 Px=0.1 P(1,1)=0.03

X=1 Y=2 Px=0.3 Px=0.05 P(1,2)=0.015

X=1 Y=3 Px=0.3 Px=0.05 P(1,3)=0.015

X=1 Y=4 Px=0.3 Px=0.2 P(1,4)=0.06

X=2 Y=0 Px=0.2 Px=0.6 P(2,0)=0.12

X=2 Y=1 Px=0.2 Px=0.1 P(2,1)=0.02

X=2 Y=2 Px=0.2 Px=0.05 P(2,2)=0.01

X=2 Y=3 Px=0.2 Px=0.05 P(2,3)=0.01

X=2 Y=4 Px=0.2 Px=0.2 P(2,4)=0.04

We can write it in the form of a matrix:

$\begin{pmatrix} &Y=0&Y=1&Y=2&Y=3&Y=4\\X=0&0.3&0.05&0.025&0.025&0.1\\ X=1&0.18&0.03&0.015&0.015&0.06 \\ X=2&0.12&0.02&0.01&0.01&0.04\end{pmatrix}$

b) From the joint probability P(X<= 1 and Y <= 1) is equal to

$P(X\leq 1 \& Y \leq 1)=P(0,0)+P(0,1)+P(1,0)+P(1,1)\\\\P(X\leq 1 \& Y \leq 1)=0.3+0.05+0.18+0.03=0.56$

We can calculate P(X<= 1) * P(Y<=1)

$P_x(X\leq 1)=P_x(0)+P_x(1)=0.5+0.3=0.8\\\\P_y(Y\leq1)=P_y(0)+P_y(1)=0.6+0.1=0.7\\\\P_x(X\leq1)*P_y(Y\leq1)=0.8*0.7=0.56$

Both calculations give the same result.

c) Probability of no violations

$P(X+Y=0)=P(0,0)=0.3$

d) P(X + Y <= 1)

$P(X+Y \leq 1)=P(0,0)+P(0,1)+P(1,0)\\\\P(X+Y \leq 1)=0.3+0.05+0.18=0.53$

5 0

3 years ago

The sum of two numbers is 12. One number is prime and the other is composite. What are the numbers?

kompoz [17]

9 and 3. Because 9 is a composite number (3*3 = 9) and 3 is a composite number (1*3 = 3).

4 0

3 years ago

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