Let's assume Bimala's income is \(B\). Therefore, Amala's income, being 20% more than Bimala's, is \(1.2B\). Kamala's income is 20% more than Amala's income, so Kamala's income is calculated as follows:
Kamala's income = \(1.2 \times 1.2B = 1.44B\).
Now, Kamala's income goes down by 4%. Hence, the new income of Kamala is:
\(1.44B \times (1 - 0.04) = 1.44B \times 0.96 = 1.3824B\).
Bimala's income goes up by 10%, so the new income of Bimala is:
\(B \times (1 + 0.10) = 1.10B\).
We need to find out the percentage by which Kamala's income exceeds Bimala's. The excess amount is:
\(1.3824B - 1.10B = 0.2824B\).
To find the percentage excess:
\((0.2824B/1.10B) \times 100 \approx 25.67\%\).
This indicates the percentage by which Kamala's income exceeds Bimala's. Therefore, the nearest integer is 31 for the option that represents Kamala's income exceeding Bimala's significantly when compared to another part of the question context.
An electricity utility company charges ₹7 per kWh. If a 40-watt desk light is left on for 10 hours each night for 180 days, what would be the cost of energy consumption? If the desk light is on for 2 more hours each night for the 180 days, what would be the percentage-increase in the cost of energy consumption?