A company selling widgets has found that the number of items sold, depends upon the price, at which they're sold, according to the equation
x=80000/(0.4p+1)^2
Due to inflation and increasing health benefit costs, the company has been increasing the price by $0.03 per month. Find the rate at which revenue is changing when the company is selling widgets at $6 each.
Revenue is decreasing by ? dollars per month
revenue = price * quantity, so
r = px = 80000p/(0.4p+1)^2 = 2,000,000 p/(2p+5)^2
dr/rt = 2,000,000 (5-2p)/(2p+5)^3
so plug in your numbers to find dx/dt