Remember the cost cannot be a number lesser than zero. so the domain must be such that the total cost C(m) is not negative. Also the range will always be 0.5 and above provided our domain is greater than or equal to zero.
Answer:all three of them achieve the sales target together in 120 days.
Step-by-step explanation:
Given: Adam and Paul an achieve the sales target of the company in 30 days, Paul and Charles In 40 days while Charles and Adam In 60 days.
Then, the number of days taken by all of them to achieve the sales target together = 
[LCM(30,40,60)=120]
Thus, all three of them achieve the sales target together in 120 days.
14 - 9 = 5
19 - 14 = 5
24 - 19 = 5
29 - 24 = 5
It is an arithmetic sequence with differences, b = 5 and a = 9
a(n) = a + b(n - 1)
a(n) = 9 + 5(n - 1)
The answer is B