Sixteen patients in a hospital must undergo a blood test for a disease. It is known that exactly one of them has the disease. The hospital has only eight testing kits and has decided to pool blood samples of patients into eight vials for the tests. The patients are numbered 1 through 16, and the vials are labelled A, B, C, D, E, F, G, and H. The following table shows the vials into which each patient’s blood sample is distributed.

If a patient has the disease, then each vial containing his/her blood sample will test positive. If a vial tests positive, one of the patients whose blood samples were mixed in the vial has the disease. If a vial tests negative, then none of the patients whose blood samples were mixed in the vial has the disease.

**Question 1: **

Suppose vial C tests positive and vials A, E and H test negative. Which patient has the disease?

- Patient 14
- Patient 2
- Patient 6
- Patient 8

**Show Answer**

**3**

**Question 2: **

Suppose vial A tests positive and vials D and G test negative. Which of the following vials should we test next to identify the patient with the disease?

- Vial E
- Vial H
- Vial C
- Vial B

**Show Answer**

**1**

**Question 3: **

Which of the following combinations of test results is NOT possible?

- Vials A and G positive, vials D and E negative
- Vials B and D positive, vials F and H negative
- Vial B positive, vials C, F and H negative
- Vials A and E positive, vials C and D negative

**Show Answer**

**4**

**Question 4: **

Suppose one of the lab assistants accidentally mixed two patients' blood samples before they were distributed to the vials. Which of the following correctly represents the set of all possible numbers of positive test results out of the eight vials?

- {4,5}
- {5,6,7,8}
- {4,5,6,7,8}
- {4,5,6,7}

**Show Answer**

**3**

### CAT 2020 LRDI sets with Solutions

CAT 2020 LRDI set 1CAT 2020 LRDI set 2

CAT 2020 LRDI set 3

CAT 2020 LRDI set 4

CAT 2020 LRDI set 5

CAT 2020 LRDI set 6

CAT 2020 LRDI set 7

CAT 2020 LRDI set 8

CAT 2020 LRDI set 9

CAT 2020 LRDI set 10

CAT 2020 LRDI set 11

CAT 2020 LRDI set 12

CAT 2020 LRDI set 13 [Current page]

CAT 2020 LRDI set 14

CAT 2020 LRDI set 15