West middle school has classes of many different sizes during first period. The number of students in each class is shown.

Hank's pickup can travel 100 miles on 5 gallons of gas. How many gallons will Hank's pickup need to travel 80 miles?

Orlov [11]

Answer:

the answer is 4

Step-by-step explanation:

because there are 20 5's is 100 and 100 - 20 is 80 that eighty makes the five four.

7 0

3 years ago

The Alvin Secretarial Service procures temporary office personnel for major corporations. They have found that 60% of their invo

Hoochie [10]

Answer:

0.9942 = 99.42% probability that at least 6 of the invoices will be paid within ten working days

Step-by-step explanation:

For each invoice, there are only two possible outcomes. Either they are paid within 10 working days, or they are not. The probability of an invoice being paid within 10 working days is independent of other invoices. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

60% of their invoices are paid within ten working days.

This means that $p = 0.6$

A random sample of 18 invoices is checked.

This means that $n = 18$

What is the probability that at least 6 of the invoices will be paid within ten working days?

Either less than 6 are paid within 10 working days, or at least 6 are paid. The sum of the probabilities of these events is 1. So

$P(X < 6) + P(X \geq 6) = 1$

We want $P(X \geq 6)$ . So

$P(X \geq 6) = 1 - P(X < 6)$

In which

$P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)$

Then

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{18,0}.(0.6)^{0}.(0.4)^{18} \approx 0$

$P(X = 1) = C_{18,1}.(0.6)^{1}.(0.4)^{17} \approx 0$

$P(X = 2) = C_{18,2}.(0.6)^{2}.(0.4)^{16} \approx 0$

$P(X = 3) = C_{18,3}.(0.6)^{3}.(0.4)^{15} = 0.0002$

$P(X = 4) = C_{18,4}.(0.6)^{4}.(0.4)^{14} = 0.0011$

$P(X = 5) = C_{18,5}.(0.6)^{5}.(0.4)^{13} = 0.0045$

$P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0 + 0 + 0 + 0.0002 + 0.0011 + 0.0045 = 0.0058$

Finally

$P(X \geq 6) = 1 - P(X < 6) = 1 - 0.0058 = 0.9942$

0.9942 = 99.42% probability that at least 6 of the invoices will be paid within ten working days

6 0

4 years ago

Right triangles abc and dbc with right angle c are given below. If cos(a)=15,ab=12 and cd=2, find the length of bd.

dmitriy555 [2]

see the attached figure to better understand the problem

we have that

$cos(A)=\frac{1}{5} \\ AB=12\ units\\ CD=2\ units$

Step 1

Find the value of AC

we know that

in the right triangle ABC

$cos (A)=(AC/AB)\\AC=AB*cos(A)$

substitute the values in the formula

$AC=12*(1/5)\\ AC=2.4\ units$

Step 2

Find the value of BC

we know that

in the right triangle ABC

Applying the Pythagorean Theorem

$AB^{2} =AC^{2}+BC^{2}\\ BC^{2}=AB^{2} -AC^{2}$

substitute the values

$BC^{2}=12^{2} -2.4^{2}\\BC^{2}= 138.24\\ BC=11.76\ units$

Step 3

Find the value of BD

we know that

in the right triangle BCD

Applying the Pythagorean Theorem

$BD^{2} =DC^{2}+BC^{2}$

substitute the values

$BD^{2} =2^{2}+11.76^{2}$

$BD=11.93\ units$

therefore

the answer is

the length of BD is 11.93 units

8 0

3 years ago

Read 2 more answers

[01.02]

frutty [35]

Answer:

d

Step-by-step explanation:

if x =3 and f(x) =x2-2x+6 then 9=f

3 0

3 years ago

I need help plz percent equations blank % of 9,000 = 6,750

Nata [24]

Answer:

6750:9000*100 =

(6750*100):9000 =

675000:9000 = 75

Now we have: 6750 is what percent of 9000 = 75

Question: 6750 is what percent of 9000?

Percentage solution with steps:

Step 1: We make the assumption that 9000 is 100% since it is our output value.

Step-by-step explanation:

6750:9000*100 =

(6750*100):9000 =

675000:9000 = 75

Now we have: 6750 is what percent of 9000 = 75

Question: 6750 is what percent of 9000?

Percentage solution with steps:

Step 1: We make the assumption that 9000 is 100% since it is our output value.

7 0

3 years ago