Claire Littleton has discovered that the change in Product A demand in any given week is inversely proportional to the change in sales of Product B in the previous week. That is, if sales of B rose by X% last week, sales of A can be expected to fall by X% this week.

A. Write the equation for next week's sales of A, using the variables A = sales of Product A, B = sales of Product B, and t = time. Assume that there will be no shortages of either product.

B. Last week, 100 units of A and 90 units of B were sold. Two weeks ago, 75 units of B were sold. What would you predict the sales of A to be this week?