A carpenter hammers nails each day at work. During the first hour she can hammer 120 nails, the second hour 100 nails, the third hour 90 nails, the fourth hour 60 nails, and the fifth hour 10 nails. Her marginal product in the third hour is nails.

90

Explanation:

Marginal product is the change in total output when an additional unit of input is added. In this example the unit of input is every 1 hour spend on work and output is amount of output for the additional hour. Third hour is the one additional hour used in which 90 nails have been hammered. So, marginal product for third hours is 90 nail.

you can lose ranking 2 ways.

1) you don't have enough points due to you expending them by asking questions/your answers are deleted.

2) your brainliest's expired. this means that brainliests, once they exceed the 30 day limit, expires. this is to ensure that you continue to contribute into the community at a constant rank if you want to continue to have/exceed the rank you have right now.

if you go to profile, and click "show more information" located on the bottom left of the box with your information (on top of the questions answered, questions asked, and friends), you will be given the following information (example):

member since : 02/13/2017, 18: 11

questions answered: 9741

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no. of brainliest answers: 1575

brainliest answers in last 30 days: 10

warnings: 0 view

questions/answers reported: 2637

questions/answers incorrectly reported: 64

look at the "brainliest answers in the last 30 days". this is the one that will affect your rank other than your points. again, once your brainliest expires (was earned 31+ days ago), it will not be counted.

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answer: a. the kind of population living in your neighbourhood.

the census explorer data tool by the us census bureau allows the user to zoom in on any neighbourhood within the united states and find the kind of people residing in that by race and age.  

the tool needs to needs to be used twice – once in order to find what type of people reside in a neighbourhood, and then to see the age groups of the people in the same neighbourhood.