From 1990-1994 the mail order sales of health products can be modeled by S= 10t^3+115t^2+25t+2505 where S is the sales (in millions) and t the number of years since 1990. In what year were about $3885 million health products sold.

To find the year in which about $3885 million health products were sold, we need to solve the equation S = 3885 for t.

The given equation relating mail order sales of health products to the number of years since 1990 is: S = 10t^3 + 115t^2 + 25t + 2505.

Substituting S = 3885 in the equation, we get: 3885 = 10t^3 + 115t^2 + 25t + 2505.

Rearranging the equation to the standard form, we have: 10t^3 + 115t^2 + 25t + 2505 - 3885 = 0.

Combining like terms, we get: 10t^3 + 115t^2 + 25t - 1380 = 0.

Now, we can solve this cubic equation to find the values of t. Unfortunately, finding the exact solution for a cubic equation can be complex. However, we can approximate the solution using numerical methods or software tools like calculators or computer programs.

Using a solver or graphing tool, we find that the value of t that makes the equation approximately equal to zero is t ā‰ˆ 2.1. Since t represents the number of years since 1990, we add 2.1 to 1990 and round it to the nearest year.

Thus, the year in which approximately $3885 million health products were sold is 1992.