Please help. I am not sure how to figure this out.

Thanks.

A silversmith mixed 25g of a 70% silver alloy with 50 grams of a 15% silver alloy What is the percent concentration of the resulting alloy?

A hospital staff member mixed a 65% disinfectant solution with a 15% disinfectant solution. How many leaders of each were used to make 50L of a 40% disinfectant solution?

A jeweler mixed 15g of a 60% silver allow with 45g of a 20% silver allow. What is the percent concentration of silver in the resulting alloy?

A 750ml solution is 4% hydrogen peroxide. How much more hydrogen peroxide is in a 850ml solution that is 5% hydrogen peroxide?