Question

A metal alloy weighing 6 kg and containing 4% iron is melted and mixed with 2 kg of a different alloy which contains 56% iron. What percent of the resulting alloy is iron?

Answer 1

6kg of an alloy that has 4% iron ---> 0.04*6kg of iron
same logic with the other alloy ---> 0.56*2kg of iron

add these together

divide by the total amount of metal you have (6kg + 2kg = 8kg)

convert to a %