John needs 20 grams of a 54% acid solution for his science project his school's science lab has bottles of 30% and 60% solution. How many grams of each should he use? PLS RESPOND QUICKLY I NEED HELP TAKE ALL THE POINTS I CAN GIVE YOU

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect