This kind of problem mainly involves the following quantities:

Purchase price, selling price and pure profit (single commodity profit). Quantity, total profit (profit of all goods sold)

It is enough to distinguish the relationship between these quantities.

Analysis: If there is no reasonable purchase price and sale price for this problem, there is no need to worry.

Solution: If the price is reduced by X yuan, then

Keywords purchase price, sale price, simple profit, quantity, total profit,

- - 44 20 20×44

-- 44 x 20+5 x(44 x)(20+5 x)

That is (44-x)(20+5x)= 1600.

Solve the equation to get the solution, x=4 or x=36.

Other questions can be filled in according to the above table, and it is easy to do equations. )