Answer:
21.77% probability that the proportion who are satisfied with the way that things are going in their life exceeds 0.85
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
For proportions p in a sample of size n, we have that 
In this problem:

In a sample of 100 Americans, what is the probability that the proportion who are satisfied with the way that things are going in their life exceeds 0.85
This is 1 subtracted by the pvalue of Z when X = 0.85. So



has a pvalue of 0.7823
1 - 0.7823 = 0.2177
21.77% probability that the proportion who are satisfied with the way that things are going in their life exceeds 0.85
So 12 = 2 + 20t -5t^2
5t^2 -20t + 10=0
t^2 -4t + 2 = 0
Use quadratic formula to solve
Simplify 8/10
(4*2)/(5*2)
2/2=1
Thus,
8/10=4/5
Now, compare 4/5 and 3/5.
Hope this helps!
8, 17/12 9, 9/24 10, 13/10 11, 11/10