Answer:

Step-by-step explanation:
Given : The formula 
We have to rearrange the given formula for 
Consider the given formula 
Multiply both side by 2, we have,

Divide both side by
, we have,

Simplify, we get,

Thus,
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
Step-by-step explanation:
V = 1/3 pi r^2 h
root(V ÷ 1/3 pi) = h
False, it's always on the vertex of the parabola.