A merchant has coffee worth 20.00 a pound that she wishes to mix with 50 pounds of coffee worth 50 dollar a pound to get a mixture that can be sold for 40 dollar a pound. How many pounds of the 20 dollar coffee should be used

From the given question, the following equation may be formed:

Quantity1 :Let x = Quantity of pounds of the 20 dollar coffee that should be used

Price1: Price of the coffee per pound = worth 20.00 a pound

Quantity2: 50 pound

Price2: 50 dollar a pound

We have to get a mixture that can be sold for 40 dollar a pound.

(20 * x) + (50 * 50) = 40 * (x + 50)

20x + 2500 = 40x + 2000

20x - 40x = 2000 - 2500

-20x = -500

-20x *-1 = -500 *-1

20x = 500

x = 500/20 = 25

25 pounds of the 20 dollar coffee should be used with with 50 pounds of coffee worth 50 dollar a pound to get a mixture that can be sold for 40 dollar a pound