Which type of study best describes the following research most likely to be done?

a researcher is testing new weight loss supplements. the researcher decides to sample two groups. the first group of subjects, the researcher labeled group 'a'. the researcher plans to give a placebo that looks like the real medicine but is just a sugar pill to group 'a'. the second group, group 'b', will be given the real medicine. the researcher knows which participants got the placebo and which received treatment but the participants don't know.

group of answer choices

blind study

double blind study

open study

closed study

(50 ) mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.