Suppose you want to plot the probability distribution that you will make money manufacturing widgets. You have a table of the probabilities associated with the various prices you might be able to negotiate from a widget-component supplier; you have a table of the probabilities associated with the costs of assembling the widgets; and you have a table of the probability of the prices that you might be able to sell the widgets for.
I presume one way to do it would be to proceed by brute force and multiply the probabilities for each possible combination. Is there a more efficient way to compute the answers?
Practically speaking, is there a way this can be done more efficiently using a spreadsheet program?