Teaching social skills, such as turn-taking or entering a group, has what effect on children? a. it contributes to arrogant behavior. b. it contributes to negative experiences and negative self-esteem. c. it artificially boosts self-esteem. d. it enables children

Raul has one solution that is 20% acid by volume and one solution that is 50% acid by volume. he plans to mix together some of each solution to create 30 milliliters of a solution that is 40% acid by volume. how many milliliters of the 20% acid solution should raul use to create the 40% acid solution? can someone explain this to me? i know that the answer is 10 milliliters, but i don't know how to get it.