Answer:
number of students in a van=12
number of students in a bus=52
Step-by-step explanation:
let number of students in a van=x
number of students in a bus=y
1x+6y=324 ...(1)
9x+3y=264 ...(2)
multiply (2) by 2
18x+6y=528 ...(3)
(3)-(1) gives
17x=204
x=204/17=12
put in (1)
12+6y=324
6y=324-12=312
y=312/6=52
Answer:

Step-by-step explanation:
Hello, let's note v the rate of the boat and r the rate of the current. We can write the following

It means that

But we can as well use the second equation:

and then

Hope this helps.
Do not hesitate if you need further explanation.
Thank you
Answer:
The approximated value of the standard deviation is 0.35.
Step-by-step explanation:
According to the Central Limit Theorem if we have an unknown population with mean <em>μ</em> and standard deviation <em>σ</em> and appropriately huge random samples (<em>n</em> > 30) are selected from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.
Then, the mean of the distribution of sample means is given by,

And the standard deviation of the distribution of sample means is given by,

The information provided is:
<em>n</em> = 100
<em>σ</em> = 3.5
<em>μ</em> = 66
As the sample size is quite large, i.e. <em>n</em> = 100 > 30, the central limit theorem can be applied to approximate the sampling distribution of sample mean by the Normal distribution.
Then the approximated value of the standard deviation of sampling distribution of sample mean is:


Thus, the approximated value of the standard deviation is 0.35.
Answer:
A) a²-2a+2a-4 the a is correct check my explanation to understand the answer.
Step-by-step explanation:
(a+2)(a-2)= a²-2a+2a-4
Answer:
15/14
Step-by-step explanation: