Why would someone give you the answer if you are in detention? I will tell you the first step which is to get rid of the -3 by adding positive three to both sides of the equation. Then from there, you should know what to do! Pay attention in class, and stop giving your teacher trouble!

8 0

3 years ago

Carl and Bob can demolish a building in 6 days, Anne and Bob can do it in 3, Anne and Carl in 5. How many days does it take all

nata0808 [166]

Answer:

59/20 days or 2.95 days

Step-by-step explanation:

Let Carl do the job in c days, Anne- in a, and Bob in b days

Then the portion of job they can do is 1/c, 1/a and 1/b

As per given we have below equations:

1/c + 1/b= 1/6
1/a + 1/b = 1/3
1/a + 1/c = 1/5

Sum of all 3 equations gives us:

2(1/a + 1/b + 1/c) = 1/6 + 1/3 + 1/5
2(1/a + 1/b + 1/c) = 5/30 + 10/30 + 6/30
2(1/a + 1/b + 1/c) = 21/30
2(1/a + 1/b + 1/c) = 7/10
1/a + 1/b + 1/c = 7/20

It means all three together can complete 7/20 of the job in one day

The rest of the job is done by Anne and Bob:

1 - 7/20 = 13/20

As Anne and Bob can do 1/3 of the job in one day, they need time to complete the rest:

13/20:1/3 = 39/20

Add 1 day to this to find overall time:

1 + 39 /20 = 59/20 days or 2.95 days

4 0

3 years ago

The university police department keeps track of the number of tickets it write in a year. Last year the campus police wrote 1460

AlladinOne [14]

Answer:

Step-by-step explanation:

We are given that Ticket writing on campus follows a Poisson process.

Last year the campus police wrote 1460 tickets

So, $X \sim Poisson (1460 / year)$

1 year = 365 days

So, E(Y) = $\frac{1460}{365}=4$

So, the standard deviation of the number of tickets written per day by the campus police = $\sqrt{4} =2$

Hence the standard deviation of the number of tickets written per day by the campus police is 2

5 0

3 years ago