20 pounds of a dry powder drug with a 50% concentration needs to be mixed with how many pounds of the dry powder drug with a 30% concentration to get a 40% concentrated solution?

Afamily has two cars. the first car has a fuel efficiency of 25 miles per gallon of gas and the second has a fuel efficiency of 15 miles per gallon of gas. during one particular week, the two cars went a combined total of 1025 miles, for a total gas consumption of 55 gallons. how many gallons were consumed by each of the two cars that week?