Final answer:
The task involves finding an exponential function for stamp cost over time, determining the growth rate, predicting future costs, and calculating savings from purchasing Forever Stamps. The presented figures seem to have typos and require clarification for precise calculations.
Step-by-step explanation:
The student has asked to find a function S(t) representing the cost of a first-class postage stamp t years after 1965, with known costs in 1965 and 2010. This is followed by determining the growth rate, predicting future costs and calculating potential savings with the Forever Stamp.
Exponential Growth Formula
Given the costs in 1965 (44 cents) and 2010 (40e cents), which indicate an exponential growth, the general form of the exponential function is S(t) = a * e(rt). The equation is solved using the given values, where a is the initial amount, r is the growth rate, and t is time.
Growth Rate Calculation
The growth rate r can be found by using the two known cost values for 1965 and 2010, and then can be used to predict costs for future years. The apparent misprint of costs as '44' and '40e' makes it challenging to provide accurate calculations without the correct figures.
Savings Calculation
To calculate the savings from purchasing Forever Stamps, one would need to compare the costs of using Forever Stamps against the costs of stamps in subsequent years. Assumptions are made regarding price increases based on the predicted costs from part c.