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

Question

Coloured strips are printed on a transparent sheet as shown below. The bottom half of this sheet is folded backwards along the PQ axis to form a semi-circle. Which of the option(s) will be a part of the resultant semi-circle?

Answer 1

Step 1: Read the peak window from the bar chart.
New cases rise sharply from week 5 (264) through week 6 (367) to week 7 (411), the single highest bar on the chart, so the outbreak's peak sits inside this five-to-seven week stretch.

Step 2: Check the cumulative total at week 10 (statement B).
Add the ten weekly values in two groups to keep the arithmetic manageable: weeks 1 to 5 give \( 6+22+73+124+264 = 489 \), and weeks 6 to 10 give \( 367+411+256+222+119 = 1375 \).
\[ 489 + 1375 = 1864 \]
Active cases with 700 recovered: \( 1864 - 700 = 1164 \), which does not match the 1194 claimed.

Step 3: Check the shape of the red line (statement C).
A cumulative line only ever climbs or flattens out; it cannot fall back toward the axis once cases have occurred, so this statement fails on the basic shape of a running total.

Step 4: Check the week 15 total (statement D).
Adding weeks 12 to 15: \( 116+78 = 194 \), then \( 194+72 = 266 \), then \( 266+30 = 296 \), not the 202 claimed.
Only statement A survives all four checks.
\[ \boxed{\text{A}} \]

Answer 2

A third way through this is to test each statement against a single guiding question: does it follow strictly from the definitions of "new cases" and "cumulative cases", or does it need an extra assumption the chart does not support?

A: This only needs the plain weekly bar values, which climb steadily to their single highest point at week 7, right after a sharp rise beginning in week 5. No extra assumption is needed for this to hold.
B: Working the running total up to week 10 in one pass, \( 6+22+73+124+264+367+411+256+222+119 \), step by step gives 1864. Subtracting the stated 700 recovered gives 1164 active cases, so the claimed 1194 does not follow from the chart.
C: Because the red line only ever adds new cases on top of the previous total, it is mathematically unable to return to the x-axis unless the whole outbreak involved zero cases from the start, so this statement does not follow from how a cumulative total behaves.
D: Summing only the most recent four weeks before week 15, since anyone earlier has already recovered under this assumption, gives \( 116+78+72+30 = 296 \), not the 202 stated.

Statement A is the only one that follows directly from the chart without needing an unsupported assumption.

So the correct answer is A.

Answer 3

A third way through this is to test each statement against a single guiding question: does it follow strictly from the definitions of "new cases" and "cumulative cases", or does it need an extra assumption the chart does not support?

A: This only needs the plain weekly bar values, which climb steadily to their single highest point at week 7, right after a sharp rise beginning in week 5. No extra assumption is needed for this to hold.
B: Working the running total up to week 10 in one pass, \( 6+22+73+124+264+367+411+256+222+119 \), step by step gives 1864. Subtracting the stated 700 recovered gives 1164 active cases, so the claimed 1194 does not follow from the chart.
C: Because the red line only ever adds new cases on top of the previous total, it is mathematically unable to return to the x-axis unless the whole outbreak involved zero cases from the start, so this statement does not follow from how a cumulative total behaves.
D: Summing only the most recent four weeks before week 15, since anyone earlier has already recovered under this assumption, gives \( 116+78+72+30 = 296 \), not the 202 stated.

Statement A is the only one that follows directly from the chart without needing an unsupported assumption.

So the correct answer is A.