Answer:
2/7 or 0.2857
Step-by-step explanation:
The expected time before the first bulb burns out (two bulbs working) is given by the inverse of the probability that a bulb will go out each day:

The expected time before the second bulb burns out (one bulb working), after the first bulb goes out, is given by the inverse of the probability that the second bulb will go out each day:

Therefore, the long-run fraction of time that there is exactly one bulb working is:

There is exactly one bulb working 2/7 or 0.2857 of the time.
Answer: c
=
3
f
y
−
12
m
y
Step-by-step explanation:
Isolate the variable by dividing each side by factors that don't contain the variable.
Scenarios B, D, and F require a police officer. In scenario B, 1:00-2:00pm, and scenario F, 5:00-6:00pm, there are 24 cars. In scenario D, 3:00-4:00pm, there are 21 cars. Both 24 and 21 are greater than 17, so a traffic officer is needed. However, in other scenarios, the number of cars are all less than 17, and no officer is needed.
Answer:
Option D : $20
Step-by-step explanation:
The average total cost to produce 100 oatmeal cookie = $0.25 per cookie.
So, total cost for 100 cookies will be =
dollars
The company’s marginal cost is constant at $0.10 for all oatmeal cookies produced.
When 50 cookies are produced, the marginal cost will be =
dollars
The total cost to produce 50 oatmeal cookies =
dollars
Hence, option D is correct.