Answer:
y=50
x=30
z=100
Step-by-step explanation:
x+20=y
2y=z
x+y+z=180
x+y+2y=180
3y+x=180
-y+x=-20
4y=200
y=50
x=30
z=100
Answer:
$74.53
Step-by-step explanation:
16%=0.16
0.16*64.25+64.25
=(0.16+1)*64.25
=$74.53
Answer:
$2,070
Step-by-step explanation:
1200*0.0725=870
the amount of tax is $870
1200+870=2070
Answer:
0.1587 = 15.87% probability that a person will wait for more than 9 minutes.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean
and standard deviation
, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.
The mean waiting time is 6 minutes and the variance of the waiting time is 9.
This means that 
Find the probability that a person will wait for more than 9 minutes.
This is 1 subtracted by the p-value of Z when X = 9. So



has a p-value of 0.8413.
1 - 0.8413 = 0.1587
0.1587 = 15.87% probability that a person will wait for more than 9 minutes.