Answer:
18.67% of bills are greater than $131
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.
In this problem, we have that:
What proportion of bills are greater than $131
This proportion is 1 subtracted by the pvalue of Z when X = 131. So
has a pvalue of 0.8133
1 - 0.8133 = 0.1867
18.67% of bills are greater than $131
Answer:
First look at the number of bricks alone.
Going from 50 bricks to 60 bricks is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 60/50
Next look at the time alone.
Going from 30 minutes to 20 minutes is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 30/20
Now you can just multiply everything.
= 5*60/50*30/20
= 5*6/5*3/2
= 90\10
= 9.
Answer:
Step-by-step explanation:
Let x - hours Carlos drove ; Let y - hours Maria drove
Equation 1: x + y = 4.4
x = 4.4 - y
Equation 2: 55x + 50y = 233
55(4.4 - y) + 50y = 233
242 - 55y + 50y = 233
-5y = 233-242
-5y = -9
y=9/5 or 1.8 hours Maria drove
To find time Carlos drove:
x=4.4 - 1.8
x = 2.6 hours
