The rate of change in sales S is inversely proportional to time t (t > 1), measured in weeks. Find S as a function of t when the sales after 2 and 4 weeks are 200 units and 300 units, respectively.

A tractor has an initial price of $8000.00 and sells for $1100.00 after 23 years. Assume that the tractor's value depreciates linearly with the passing years. (a) Let V represent the tractor's value in dollars and let t represent the number of years since the tractor was purchased. Write a formula to express the tractor's value as a function of time: V(t) = ... ... (b) Horizontal intercept of the value function V(t): ... Vertical intercept of the value function V(t):

In 2000, mobile handset sales totaled $414.99 million. In 2005, the total was $778.75 million. Let M = M(t) denote total mobile handset sales in year t. What was the average rate of change per year in M(t) from 2000 to 2005? (Round your answer to two decimal places.) million dollars per year

Element X is a radioactive isotope such that its mass decreases by 20% every year. Ifan experiment starts out with 730 grams of Element X, write a function to representthe mass of the sample after t years, where the monthly rate of change can be foundfrom a constant in the function. Round all coefficients in the function to four decimalplaces. Also, determine the percentage rate of change per month, to the nearesthundredth of a percent.