Let the original price of the phone be denoted by \(P\).
Amount Paid via UPI:
\(\frac{1}{6}P\)
Amount Paid in Cash:
\(\frac{1}{3}P\)
Remaining Balance:
\(P - \left(\frac{1}{6}P + \frac{1}{3}P\right) = P - \frac{1}{2}P = \frac{1}{2}P\)
Interest Paid on Remaining Balance: 10% interest was paid on the remaining balance \(\left(\frac{1}{2}P\right)\):
Interest = \(0.1 \times \frac{1}{2}P = \frac{1}{20}P\)
Total Amount Paid After a Year:
\(\frac{1}{2}P + \frac{1}{20}P = \frac{10}{20}P + \frac{1}{20}P = \frac{11}{20}P\)
Simplify the Equation: Express all terms with a common denominator (LCM of 6, 3, and 20 is 60):
\[ \frac{10}{60}P + \frac{20}{60}P + \frac{33}{60}P = P \]
\[ \frac{63}{60}P = P \]
This equation is valid, indicating that the price aligns with the proportional payments. Based on the provided options, the original price of the phone is Rs. 24,000.