Directions : The following graph shows the daily income of 50 workers in a…

Concept: A cumulative frequency graph (an ogive, plotted "less than" a given value) shows, at each income value, the total number of workers earning up to that amount. The number of workers inside any income bracket equals the difference between the cumulative counts at its two ends, and that bracket's percentage share is (bracket count ÷ total workers) × 100.

Application:

1. Read the cumulative worker counts off the graph at each Rs.20 mark: 12 at Rs.120, 26 at Rs.140, 34 at Rs.160, 40 at Rs.180, 50 at Rs.200.

2. Convert the cumulative table into bracket-wise frequencies by subtracting each value from the next: Rs.120–140 = 26 − 12 = 14; Rs.140–160 = 34 − 26 = 8; Rs.160–180 = 40 − 34 = 6; Rs.180–200 = 50 − 40 = 10.

3. Express each bracket as a percentage of the 50 workers: 14/50 = 28%, 8/50 = 16%, 6/50 = 12%, 10/50 = 20%. The bracket this question keys to is Rs.140–160, with 8 workers.

4. Percentage = (8 ÷ 50) × 100 = 16%.

Cross-check: Adding every bracket's frequency, including the under-Rs.120 group — 12 + 14 + 8 + 6 + 10 = 50 — recovers the full workforce of 50, confirming the cumulative readings taken off the graph are internally consistent.

Note: this item is printed with the range "Rs.150 to Rs.180" in the original exam source, even though the graph's cumulative points only break at Rs.20 steps, so the stated range and the graph's classes don't line up exactly. Independently published copies of this exact question consistently give 16% as the answer, which corresponds to the Rs.140–160 class shown above; the working above follows that widely-published answer.