Based on the given sequence of numbers above, the best definition of it would be a geometric sequence. It is a geometric sequence because term of the sequence of numbers after the first is found by multiplying the previous one by a fixed, non-zero number, and the sequence shows a common ratio.
21/7=3mins per wall with 5 people.
Because we assume that all of the people paint at the same rate, 3 X 5=15 mins for one person working alone.
15/3=5 mins per wall with 3 people X 10 people= 50 mins for 3 people to paint 10 walls.
The answer is 50 mins.
The volume of a cone is
V = (1/3)πr³
We are given with radius and the height of cone, so we can solve for the radius as function of water level using ratio and proportion
3/9 = r/h
r = h/3
Substituting
V = πh³/81
Taking the derivative
dV/dt = πh²/27 dh/dt
Solving for dh/dt given
dV/dt = 10 m³/s
and
h = 3 m
dh/dt = 9.55 m/s