Answer:
960
Step-by-step explanation:
You have to figure out what 1/4th of 640 is, which is 160.
It says that number is 1/6th of boys, so you multiply by the inverse.
160x6 = 960
Questions:
(a) What is a simplified expression for (x + y) – (x – y)?
(b) Carlotta thinks that
is the same as
. Which statement shows that it is NOT the same?
Answer:


Step-by-step explanation:
Solving (a):
Given

Required
Simplify

Open brackets

Collect Like Terms



Solving (b):
Given
and 
Required
Which expression shows they are not the same
The expression that shows this is:

Take for instance; y=2
Substitute 2 for y in 

Evaluate all exponents



The above expression supports 
A: Deena subtracted 25, instead of adding it.
B: 9x - 25 = 88.
C: no idea
Answer: 1.The total cost = 4x + 2y
2.The total cost = 2y + 4x
3.The total cost = 6x + 4y
4.The total cost = 4y + 6x
Step-by-step explanation: mark me brailyest and like aslo follow
Answer:
The critical value that should be used in constructing the interval is T = 5.8408.
The 99% confidence interval for the true mean yield is between 2.943 bushels per acre and 96.268 bushels per acre.
Step-by-step explanation:
We have the standard deviation of the sample, so we use the students t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 4 - 1 = 3
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 3 degrees of freedom(y-axis) and a confidence level of
. So we have T = 5.8408. This is the critical value.
The margin of error is:
M = T*s = 5.8408*7.99 = 46.668 bushels per acre
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 49.6 - 46.668 = 2.943 bushels per acre.
The upper end of the interval is the sample mean added to M. So it is 49.6 + 46.668 = 96.268 bushels per acre.
The 99% confidence interval for the true mean yield is between 2.943 bushels per acre and 96.268 bushels per acre.