Study the charts given below carefully and answer the following questions. Pie…

Concept

In a combined pie-chart and table set, each zone's TOTAL is found from its pie percentage of the grand total. When a stream is split into two parts (Science and Commerce) and only one part is tabulated, the other part is the simple complement:

Commerce in a zone = (that zone's total) - (that zone's Science). The total of any zone = (zone's pie %) x (grand total).

Note on wording: when a question asks 'how much more' but the first quantity turns out to be the smaller one, the standard exam reading is the MAGNITUDE of the difference between the two quantities. Here the Western Commerce count is in fact the smaller side, so the required value is the size of the gap, not a signed amount.

Step-by-step working

1. Grand total of all students = 4000.

2. Western zone is 30% of the total, so Western total = 30% of 4000 = 1200.

3. Science students in Western zone (from the table) = 750, so Commerce in Western = 1200 - 750 = 450.

4. Science students in Northern + Eastern + Southern zones (read directly from the table) = 400 + 310 + 430 = 1140.

5. Required difference = | 450 - 1140 | = 690.

Zone-wise breakdown

Cross-check

Comparing the two quantities directly: the combined Science count of the three named zones is 1140 and the Western Commerce count is 450, so the magnitude of their difference is 1140 - 450 = 690.