What is the percentage contribution of power sector to total CO2 emissions in…

Concept: The percentage contribution of one part to a whole is (part ÷ whole) × 100. In a year-wise, sector-wise emissions table the whole for any single year is that year total taken across every sector — the row total — not a column total for one sector and not a multi-year grand total. Choosing the correct denominator is the entire skill being tested.

Application — year 2008

1. Read the 2008 row of the table: Power = 700, Industry = 400, Commercial = 300, Agriculture = 150, Domestic = 150 (million metric tons).

2. Total CO2 emissions in 2008 = 700 + 400 + 300 + 150 + 150 = 1700 million metric tons.

3. Power sector share = (Power in 2008 ÷ Total in 2008) × 100 = (700 ÷ 1700) × 100.

4. Simplify the fraction: 700 ÷ 1700 = 7 ÷ 17 = 0.41176…

5. Convert to a percentage: 0.41176… × 100 = 41.176…%, which rounds to about 41.18%.

Cross-check

• Reverse the calculation: 41.18% of 1700 = 0.4118 × 1700 ≈ 700, which is exactly the power figure the table gives for 2008.

• Bound it without dividing: two-fifths of 1700 is 680 and one-half of 1700 is 850. Since 700 lies between 680 and 850, the share must lie between 40% and 50%.

• Watch the denominator: dividing 700 by the five-year power column total (500 + 600 + 650 + 700 + 800 = 3250) gives about 21.5%, and dividing by only the three largest sectors of 2008 (700 + 400 + 300 = 1400) gives 50%. Both use a whole the question did not ask for.

Result: the power sector accounted for about 41.18% of the total CO2 emissions of the country in 2008.