Answer:
You should recruit a total of 525 subjects for the whole study.
Step-by-step explanation:
The question states that you want 175 subjects per group for 3 groups. This indicates that we need to either multiply 175 times 3, or we can add 175 three times to get the total number of subjects we would need to recruit. Group 1 should have 175, Group 2 should have 175 and Group 3 should have 175. Whether we multiply 175 x 3 or add 175+175+175, we get a final anser of 525.