Let Thahir’s total income be \( I \).
After deducting family and personal expenses, the remaining income is:
\[ I - (0.32I + 0.23I) = I - 0.55I = 0.45I \]
He spends 70% of the remaining amount on children’s education:
\[ 70\% \times 0.45I = 0.315I \]
The remaining amount, which is his savings, is:
\[ 0.45I - 0.315I = 0.135I \]
Thus, the savings are 13.5% of his income. The correct answer is (D) 13.5.
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?