A bike is available for Rs. 39000 cash or Rs. 17000 as cash downpayment followed by five monthly instalments of Rs. 4800 each. What is the rate of interest per annum under the instalment plan? एक बाइक 39000 रू. नकद देकर या 17000 रू. नकद और 5 मासिक किस्त जो प्रत्येक 4800 की होगी अदा करके खरीद सकता है। ज्ञात कीजिए किस्त के लिए ब्याज की दर प्रति वर्ष क्या है?
A
Correct answer
Explanation
Cash price = 39000. Installment plan: 17000 down + 5 × 4800 = 17000 + 24000 = 41000. Extra amount = 41000 - 39000 = 2000. This is interest on the declining balance. Principal for first month = 39000 - 17000 = 22000. Using simple interest approximation: Total interest = P × r × t. 2000 = 22000 × r × (5/12). Solving: r = 2000 × 12 / (22000 × 5) = 24000 / 110000 = 0.2182 or 21.82%. However, this doesn't match option A. The actual method uses monthly reducing balance. After calculation, the annual rate comes to approximately 38.71%. Options B, C, and D are incorrect.