Research suggests that laughter improves people’s emotional and physical well-being. Write a research-based essay to inform the reader about the positive effects of laughter on emotional and physical health. Properly cite research evidence to inform the audience about the topic. << read less stylesnormal.

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.