The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!
This is a combination of 20 studants, 6 to 6:
Answer: Company A would be a better deal for number of minutes over 200
Step-by-step explanation:
Let x represent the number of minutes that you would use with either company A or company B.
Company A has a monthly charge of $10 plus 5¢ a minute for each minute of long distance calls. It means that the cost of x minutes of long distance call is
10 + 0.05x
Company B has a monthly charge of $8 plus 6¢ a minute for long distance calls. It means that the cost of x minutes of long distance call is 10 + 0.05x
8 + 0.06x
For Company A to be a better deal, it means that
10 + 0.05x < 8 + 0.06x
10 - 8 < 0.06x - 0.05x
2 < 0.01x
0.01x > 2
x > 2/0.01
x > 200
Answer:
0.42 is closest to the proportion of customer purchase amounts between $14.00 and $16.00
Step-by-step explanation:
Mean = 
Standard deviation = 
We are supposed to find the proportion of customer purchase amounts between $14.00 and $16.00
P(14<x<16)
Formula : 
At x = 14


Refer the z table for p value
P(x<14)=0.1922
At x = 16


Refer the z table for p value
P(x<16)=0.6141
P(14<x<16)=P(x<16)-P(x<14)=0.6141-0.1922=0.42
So, Option C is true
Hence 0.42 is closest to the proportion of customer purchase amounts between $14.00 and $16.00