Answer:
the answer is A on khan academy
Step-by-step explanation:
2x+3y+5+4x-7y-8
2x+4x+3y-7y+5-8
6x-4y-3
Answer: volunteer within each block should live in similar environments to each other when it comes to mosquitos
Step-by-step explanation:
The confidence interval for confidence level of
is

where
is the sample mean,
is the critical value for the given confidence level,
is the standard deviation of the population, and
is the sample size. The margin of error is the
term.
a) For a confidence level of
, we have
. So in order to have a margin of error of at most 25 points, we have

so Raina should collect a sample of at least 269 students.
b) A confidence interval with a higher confidence level would more closely approximate and reflect the population, so it stands to reason that Luke should collect a larger sample than Raina to meet his 99% confidence spec.
c) For a confidence level of
, we have
. Then the margin of error would at most satisfy

so that Luke should collect a sample of at least 666 students.
Let the number be the variable x
4 times the number is 4x
the sum of 8 and 4 times a number is 28
4x+8=28
4x=28-8
4x=20
x=20/4
x=5