PLZ HURRY! Kaylie wants to see how metals can be combined. She found a problem to solve. Help her solve it! How many pounds of a metal containing 20% nickel must be combined with 6 pounds of a metal containing 80% nickel to form an alloy containing 60% nickel?

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)