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3 years ago

A chemical reaction took 7380 seconds. How many hours did the reaction

Mathematics

1 answer:

Svetlanka [38]3 years ago

6 0

Answer: 2.05 hours

Step-by-step explanation: There are 60 seconds in a minute, and 60 minutes in an hour. To find the seconds in an hour, multiply 60 by 60.

60 x 60 = 3600

There are 3600 seconds in an hour. Divide 7380 by 3600 to find the number of hours.

7380/3600 = 2.05

The reaction took 2.05 hours.

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I will give brainliest and 30 points

Oksi-84 [34.3K]

Answer: 15

Step-by-step explanation:

8 0

3 years ago

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A student committee is to consist of 2 freshmen, 5 sophomores, 4 juniors, and 3 seniors. If 6 freshmen, 13 sophomores, 8 juniors

mezya [45]

<h3>Answer: 491,891,400</h3>

Delete the commas if necessary.

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

Explanation:

There are 6 freshmen total and we want to pick 2 of them, where order doesn't matter. The reason it doesn't matter is because each seat on the committee is the same. No member outranks any other. If the positions were labeled "president", "vice president", "secretary", etc, then the order would matter.

Plug n = 6 and r = 2 into the nCr combination formula below

$n C r = \frac{n!}{r!(n-r)!}\\\\6 C 2 = \frac{6!}{2!*(6-2)!}\\\\6 C 2 = \frac{6!}{2!*4!}\\\\6 C 2 = \frac{6*5*4!}{2!*4!}\\\\ 6 C 2 = \frac{6*5}{2!}\\\\ 6 C 2 = \frac{6*5}{2*1}\\\\ 6 C 2 = \frac{30}{2}\\\\ 6 C 2 = 15\\\\$

This tells us there are 15 ways to pick the 2 freshmen from a pool of 6 total.

Repeat those steps for the other grade levels.

n = 13 sophomores, r = 5 selections leads to nCr = 13C5 = 1287. This is the number of ways to pick the sophomores.

You would follow the same type of steps shown above to get 1287. Let me know if you need to see these steps.

Similarly, 8C4 = 70 is the number of ways to pick the juniors.

Lastly, 14C3 = 364 is the number of ways to pick the seniors.

-----------------------------

To recap, we have...

15 ways to pick the freshmen
1287 ways to pick the sophomores
70 ways to pick the juniors
364 ways to pick the seniors

Multiply out those values to get to the final answer.

15*1287*70*364 = 491,891,400

This massive number is a little under 492 million.

7 0

2 years ago

Tim Hortons is hiring and offers $200 every week plus $5 per hour. McDonalds offers $300 every week plus $2 per hour. State the

Ray Of Light [21]

Answer:

Assuming you want better payment each week, any number of hours above 33.333 or 33 hours and 20 minutes per week

Step-by-step explanation:

There are several ways we could do this. We could say we want to have Tim Hortons be the better employer on the first week, or after so many weeks by adjusting the hours. I am going to assume we are saying we want it to be a better employer on the first week, so the profit will be the amount made every week plus the money made per hour times the number of hours.

Let's say number of hours is H

So Tim Hortons winds up as 200 + 5H for one week and Mcdonalds will be 300 + 2H.

If you set the two expressions equal to each other you will find where they intersect, which means at that number of hours they will give the same amount of money while any amount before one of the companies will give more and after that many hours the other will. Let's go ahead and solve.

200 + 5H = 300 + 2H

3H = 100

H = 100/3

So H is about 33.333. let's check.

200 + 5(33.333) = 366.665 which rounds to 366.67 dollars

300 + 2(33.333) = 366.666 which also rounds to 366.67 dollars

So at 33.333 hours both give 366.67 dollars. Let's look at a value below it, say 32.

200 + 5(32) = 360

300 + 2(32) = 364

So you can see here Tim Hortons pays less. Now we will try 34 as a value above 33.333

200 + 5(32) = 370

300 + 2(32) = 368

Here Mcdonalds pays less. This was to show that values below 33.333 make Tim Hortonspay less and values above 33.333 make Mcdonalds pay less. In other words any value above 33.333 hours will have Tim Hortons be the better employer. And this is per week

I want to repeat, you can expand this to be multiple weeks and see which of the two becomes better in that epriod of time. This was, I think, the simplest way to answer though.

So the conditions where Tim Horton pays more isif you work more than 33.333 hours per week. This will make them pay more every single week.

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2 years ago

There are 8 books in a shelf that consist of 2 paperback books and 6 hardback books. If 4 books are selected at random without r

mixer [17]

Answer:D

Step-by-step explanation:

This is combination.

If 4 books selected out of eight book in the shelf:

(4 combination 8)= 70

For hardback selection:

Then selection of 4 books out of the hardback, it means there is no paperbach will be:

(4 combination 6)= 15

So , if at least one paperback selected will be : 70-15

That is 55

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3 years ago

A recipie needs 5/8 cups of sugar. What percent of a whole cup is that?

katen-ka-za [31]

Answer: 62.5 percent

Step-by-step explanation:

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3 years ago

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