PLLLLLLLEEEEEEEEEEEEEEASE ANSWER FAST MATH GENIUSES!!!!!!!
A coffee company wants a new flavor of Cajun coffee. How many pounds of coffee worth $ 7 a pound should be added to 30 pounds of coffee worth $ 3 a pound to get a mixture worth $ 5 a​ pound?

To get a mixture worth $ 5 a​ pound,_____ pounds of coffee should be added.