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2 years ago

How many positive integers not exceeding 1000 are not divisible by either 4 or 6?

1 answer:

7 0

$\left\lfloor\dfrac{1000}4\right\rfloor=250$

$\left\lfloor\dfrac{1000}6\right\rfloor=166$

$\left\lfloor\dfrac{1000}{\mathrm{lcm}(4,6)}\right\rfloor=\left\lfloor\dfrac{1000}{12}\right\rfloor=83$

$250+166-83=333$

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Two trains leave New York at the same time heading in opposite directions. Train A travels at 4/5 the speed of train one. After

grandymaker [24]

<h3>Answer: </h3><h3>speed of train A = 44 mph</h3>

=============================================

Work Shown:

x = speed of train A

y = speed of train B

"train A travels 4/5 the speed of train B" (I'm assuming "train one" is supposed to read "train B"). So this means x = (4/5)y

distance = rate*time

d = x*7

d = (4/5)y*7 = (28/5)y represents the distance train A travels

d = y*7 = 7y represents the distance train B travels

summing those distances will give us 693

(28/5)y + 7y = 693

5*( (28/5)y + 7y ) = 5*693

28y + 35y = 3465

63y = 3465

y = 3465/63

y = 55

Train B's speed is 55 mph

4/5 of that is (4/5)y = (4/5)*55 = 4*11 = 44 mph

Train A's speed is 44 mph

8 0

2 years ago

I need a word problem that has a negative - positive

AleksandrR [38]

Answer:

Here it is

Step-by-step explanation:

You are 58 dollars in debt, and your friend pays you 73 dollars. How much money do you have? Does that work for you?

8 0

2 years ago

48 is 32% of what number?

Irina18 [472]

Answer:

150

Step-by-step explanation:

Because I looked it up

4 0

2 years ago

The Resource Conservation and Recovery Act mandates the tracking and disposal of hazardous waste produced at U.S. facilities. Pr

aniked [119]

Answer:

(a) $E(X) = 0.383$

The expected number in the sample that treats hazardous waste on-site is 0.383.

(b) $P(x = 4) = 0.000169$

There is a 0.000169 probability that 4 of the 10 selected facilities treat hazardous waste on-site.

Step-by-step explanation:

Professional Geographer (Feb. 2000) reported the hazardous waste generation and disposal characteristics of 209 facilities.

N = 209

Only eight of these facilities treated hazardous waste on-site.

r = 8

a. In a random sample of 10 of the 209 facilities, what is the expected number in the sample that treats hazardous waste on-site?

n = 10

The expected number in the sample that treats hazardous waste on-site is given by

$E(X) = \frac{n \times r}{N}$

$E(X) = \frac{10 \times 8}{209}$

$E(X) = \frac{80}{209}$

$E(X) = 0.383$

Therefore, the expected number in the sample that treats hazardous waste on-site is 0.383.

b. Find the probability that 4 of the 10 selected facilities treat hazardous waste on-site

The probability is given by

$P(x = 4) = \frac{\binom{r}{x} \binom{N - r}{n - x}}{\binom{N}{n}}$

For the given case, we have

N = 209

n = 10

r = 8

x = 4

$P(x = 4) = \frac{\binom{8}{4} \binom{209 - 8}{10 - 4}}{\binom{209}{10}}$

$P(x = 4) = \frac{\binom{8}{4} \binom{201}{6}}{\binom{209}{10}}$

$$ P(x = 4) = \frac{70 \times 84944276340}{35216131179263320}$

$P(x = 4) = 0.000169$

Therefore, there is a 0.000169 probability that 4 of the 10 selected facilities treat hazardous waste on-site.

8 0

2 years ago

A bed is 6 1/2 feet long.the material to make a sheet for the bed is to be 1 1/2 times as long to allow for hems and tucking und

Svetllana [295]

Answer: 9 3/4 feet long

Explanation:

1 1/2 x 6 1/2 = 3/2 x 13/2 = 39/4 = 9 3/4 feet long

4 0

2 years ago