Dr/dt = 0.00025/min
V = πr^2h
dV/dt = 2πrh dr/dt
Here, r = 3.8/2 = 1.9, h = 6
dV/dt = 2π(1.9)(6)(0.00025) = 0.00285π = 0.00895 in^2/min
Consider the expression 
If h represents the number of hours it takes to repair the computer, then expression 75h represents the amount of money that repairer earns.
The expression 0.09(75h) represents the amount of money for tax Mrs. Bull has to pay. This means that tax makes up 9%.
Answer: first part 0.09(75h) represents the amount of money for tax Mrs. Bull has to pay.
Hello :
(f+g)(x) = f(x) +g(x) = (5x-2)+ (2x+1) = 7x -1