Answer:
a. $45 an hour
b. 5.25 hours
Step-by-step explanation:
a. The plumber charges $75 per job, so it is irrelevant to the number of hours they work. 45(h) is $45 multiplied by the number of hours they work.
b.
First, plug the numbers into the equation, the cost being C(h):
311.25 = 45(h) + 75
Next, subtract $75 as it is a set price that is always payed:
236.25 = 45(h)
Then, divide both sides by 45 to find how many hours were worked:
h = 5.25
Hours = $5.25
The normal rule to remember is 68-95-99.7, i.e. plus or minus three sigma corresponds to 99.7% of the probability. That leaves 0.3% in the two tails, or 0.15% in the tail above 3 sigma.
Answer: 0.15%
The answer is 3/9 or 1/3 in its simplest form
