In the lecture, we covered the "pooled-testing" problem, namely when you do blood test on large number of people, it is more efficient to pool K people's blood together to do the test: if this pooled blood sample results in negative, then you know all these people are negative, if this pooled blood sample results in positive, then you need to re-test each one of them in this group. Therefore, for each group of people, you either test once or times. Suppose is the rate of certain disease, in case , in the class, we did the calculation 0f , where is the random number of times you need to do the test. For this problem, if and , do the calculation of for =3, 4, 5, 6, 7, 8, 10, 15, 25, 35, and then determine the best .