The table shows the total electricity consumption in Singapore over three years.

1. Calculate 15.5% of the 2021 total consumption.

From the table, the total electricity consumption in 2021 is $53\,483$ GWh.

$15.5\% \times 53\,483 = \frac{15.5}{100}\times 53\,483 = 8299.865$

2. Round the answer to two significant figures.

$8299.865 \text{ GWh} \approx 8300 \text{ GWh}$
correct to two significant figures.

1. Find the increase in electricity consumption from 2020 to 2022.

Increase $= 54\,884 - 50\,779 = 4105$ GWh

2. Calculate the percentage increase using the 2020 value as the original amount.

$\text{Percentage increase}=\frac{4105}{50\,779}\times 100\% = 8.0840505\ldots\%$
So, the percentage increase is $8.09\%$ to 3 significant figures.

1. Convert the 2020 consumption from GWh to kWh and express it in standard form to two significant figures.

$50\,779\text{ GWh}=50\,779\times 10^6\text{ kWh}$

$=50\,779\,000\,000\text{ kWh}$

$=5.0779\times 10^{10}\text{ kWh}$

Correct to two significant figures,

$5.0779\times 10^{10}\approx 5.1\times 10^{10}$