To get a mixture worth $5 a pound, how many pounds should be added

Question

How many pounds of coffee worth $7 a pound should be added to 30 pounds of coffee worth $4 a pound to get a mixture worth $5 a pound

Answer 1

We can figure this out with an equation,

 

let,

 

x = pounds of coffee

 

(x+30) = total pounds of coffee when mixed

 

7x + (4 * 30) = 5(x + 30)

 

explained a bit:

(7 * how many pounds?) + (4 * 30 pounds given) = 5 ( total pounds)

 

solve for x,

15 pounds of coffee should be added.