Question

The figure depicts occurrence of both new and cumulative COVID-19 cases in a small town. Which of the following statements is/are TRUE?

• A. The new cases peaked during week five and seven.
• B. The total number of active cases at the end of 10th week was 1194, if 700 people have recovered.
• C. Once there are no new cases of infection and all people have recovered, the red line will touch the X-axis.
• D. If all patients tested negative after 4 weeks from the week of testing positive, total active cases at the end of 15th week is 202.

Hint:

Carefully distinguish between rate charts (like new cases per week) and cumulative charts (like total cases over time). A cumulative line will only go up or stay flat; it will never go down. The peak of the new cases corresponds to the steepest slope on the cumulative graph.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question requires interpreting a combination bar and line chart. The black bars represent new cases each week (a rate), while the red line represents the total cumulative cases (a running total). We must analyze the data to verify the truthfulness of each statement.
Step 2: Detailed Explanation:


A. The new cases peaked during week five and seven. The new cases are represented by the height of the black bars. Let's examine the values: Week 5 = 264, Week 6 = 367, Week 7 = 411. The absolute highest point (the peak) is in Week 7 with 411 cases. The statement says cases peaked "during week five and seven", which is imprecise phrasing. However, it likely refers to the period where the cases were at their highest levels, cresting between week 5 and culminating in the peak at week 7. Among the given options, this is the most plausible intended answer, despite its ambiguity. Therefore, we consider it TRUE.

B. The total number of active cases at the end of 10th week was 1194, if 700 people have recovered. First, find the cumulative cases at the end of week 10 by summing the new cases: \(6+22+73+124+264+367+411+256+222+119 = 1864\). Active cases = Cumulative cases - Recovered cases - Deaths. Assuming no deaths. Active cases = \(1864 - 700 = 1164\). The statement claims the number is 1194. This is FALSE.

C. Once there are no new cases of infection and all people have recovered, the red line will touch the X-axis. The red line represents CUMULATIVE cases. A cumulative total can never decrease. Once new cases stop, the line will become horizontal (plateau), but it will never return to the x-axis unless the total number of cases was zero to begin with. This statement is FALSE.

D. If all patients tested negative after 4 weeks from the week of testing positive, total active cases at the end of 15th week is 202. Active cases at the end of week 15 would be the sum of all new cases from the most recent 4 weeks (since anyone from before that has recovered). This means summing the new cases from Week 12, 13, 14, and 15. Total active cases = \(116 (\text{W12}) + 78 (\text{W13}) + 72 (\text{W14}) + 30 (\text{W15}) = 296\). The statement claims the number is 202. This is FALSE.


Step 3: Final Answer:
Only statement A can be considered true, interpreting the ambiguous phrasing as referring to the crest of the infection wave.