Work=speed times time (my equation to help me figure it out)
ok, 10 men take 84 days to complete a job
therefor, each man completes 1/10 of the job in 84 days
each man does 1/840 of the job per 1 day
so, if we had 5 more, or 15 men
15 times 1/840 times xdays=1 job complete
15/840 times xdays=1job
times both sides by 840/15
xdays=840/15
xdays=56
56 days it would take
3.2 divided by 0.4 would be 8
ANSWER
Yes,the graph passes the vertical line test.
EXPLANATION
The graph above shows a function because if we draw a vertical line across the graph anywhere, it will never intersect the graph more than once.
This is what we call the vertical line test.
Since the graph of the function passes the vertical line test, the graph shows a function.
See graph
Therefore the correct answer is option C.