Amerchant has coffee worth $80 a pound that she wishes to mix with 70 pounds of coffee worth $70 a pound to get a mixture that can be sold for $75 a pound. how many pounds of the $80 coffee should be used?

10 lbs

Step-by-step explanation:

Amount of coffee of 20$/lb = x lb

Its cost =20*x       $

Cost of other coffee =80*50=4000 $

Total amount of coffee = (x+50) lb

The final mixture costs =70$/lb

Total cost of the mixture =(x+50)*70

So,

We have the equation

(x+50)*70=20*x +4000

50*x = 500

x=10

So, amount of  20$/lb coffee = 10 lb

answer: about 22.67

step-by-step explanation: