Answer:
The number of boys in the school is;

Explanation:
Given that the ratio of boys to girls in a school is 5:4;

And there are 500 girls in the school.
The number of boys in the school will be;

Therefore, the number of boys in the school is;
Answer:
A sample of 1068 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error is:

95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
At 95% confidence, how large a sample should be taken to obtain a margin of error of 0.03 for the estimation of a population proportion?
We need a sample of n.
n is found when M = 0.03.
We have no prior estimate of
, so we use the worst case scenario, which is 
Then






Rounding up
A sample of 1068 is needed.
3)
82 + p >= 150
p>= 150 - 82
p>= 68
answer A.
4)
x/-10 > 6
x > -60
answer
x > -60
5)
5z >= - 75
z >= -75/5
z >= -15
answer
z >= -15