A drug trial is testing the effectiveness of two drugs, If 50 patients are given Drug A, 20 patients are given Drug B, and 100 patients are given a placebo, what is the probability that a patient will NOT be given a placebo?

a. 10/17
b. 7/17
c. 5/17
d. 2/17
I saw there was a problem like this and it said to add up all the patients and then put the number of patients of B over the total and simplify and I did this and got 2/17 and got it wrong, I have one more attempt to do.

7/17

70 patients are given a drug ... either A or B

100 patients are given a placebo

70 out of 170 (total) are not given a placebo ... 70 / 170

To find the probability that a patient will not be given a placebo, we need to consider the total number of patients who are not given a placebo, which is the sum of the patients given Drug A and Drug B.

Given:
Patients given Drug A = 50
Patients given Drug B = 20
Total patients = 50 + 20 + 100 = 170

Now, the probability that a patient will not be given a placebo is the ratio of the total number of patients who are not given a placebo to the total number of patients.

Probability = (Patients given Drug A + Patients given Drug B) / Total patients
Probability = (50 + 20) / 170
Probability = 70 / 170

Simplifying this fraction, we can divide both the numerator and denominator by 10:

Probability = 7 / 17

Therefore, the correct answer is b. 7/17.

To determine the probability that a patient will not be given a placebo, you need to calculate the number of patients who will not be given a placebo and divide it by the total number of patients.

In this case, you have:
- 50 patients given Drug A
- 20 patients given Drug B
- 100 patients given a placebo

To calculate the probability of not being given a placebo, add up the number of patients given Drug A and Drug B:
50 + 20 = 70

Then, divide this number by the total number of patients:
70 / (50 + 20 + 100) = 70 / 170

Now simplify the fraction:
70 / 170 = 7/17

Therefore, the correct answer is:
b. 7/17

It seems that you had the correct approach but made an error while calculating the final probability. Make sure to double-check your math, especially when simplifying fractions.