Answer:
m ≥ 0
Step-by-step explanation:
Since the cost is represented by c = 0.12m, the domain should be a positive number, this is because number of minutes can't be written in negative. Therefore, the most reasonable number for the domain would be the set of positive whole numbers which means, m≥0.
(2•7)-5
14-5= 9
So the answer is 9
<h2>
Answer with explanation:</h2>
Let
be the population mean lifetime of circulated $1 bills.
By considering the given information , we have :-

Since the alternative hypotheses is two tailed so the test is a two tailed test.
We assume that the lifetime of circulated $1 bills is normally distributed.
Given : Sample size : n=50 , which is greater than 30 .
It means the sample is large so we use z-test.
Sample mean : 
Standard deviation : 
Test statistic for population mean :-


The p-value= 
Since the p-value (0.0433834) is greater than the significance level (0.02) , so we do not reject the null hypothesis.
Hence, we conclude that we do not have enough evidence to support the alternative hypothesis that the average lifetime of a circulated $1 bill differs from 18 months.