Answer:
The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).
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
.
For this problem, we have that:
323 blacks, 86% of blacks said that they would welcome a white person into their families. This means that 
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).
1. Translate words into equation :
Brian= b
Natasha =n
N+3n=88 (because brian has 3x more than natasha u can rewrite b as 3n)
2. Solve : 4n=88 (divide by 4)
N=22 so natasha has 22 marbles and since b=3n, brian has 66 marbles