InterviewSolution
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1/3rd of a principal amount is kept at simple interest in the post office at a rate of 15% per annum, and rest is kept in the bank at compound interest at the rate of 10% per annum. Find the total amount invested if the difference between compound interest and simple interest for two years be Rs. 480.1. Rs 120002. Rs 80003. Rs 40004. Rs 16000 |
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Answer» Correct Answer - Option 1 : Rs 12000 Given: SI rate of interest = 15% CI rate of interest = 10% Difference between compound interest and simple interest for two years = Rs. 480. Formula Used: Simple Interest = (P × R × T)/100 Compound Interest = P(1 + R/100)T – P Where, P → Principal R → Rate of interest T → Time Calculations: Let the total principal be x Simple Interest in two years = ((x/3) × 15 × 2)/100 = x/10 Compond Interest in two years = (2x/3)(1 + 10/100)2 – 2x/3 ⇒ (2x/3) × 121/100 – 2x/3 ⇒ (121x/150) – 2x/3 ⇒ 21x/150 According to the querstion, ⇒ (21x/150) – (x/10) = 480 ⇒ 6x/150 = 480 ⇒ x = 12000 ∴ The total amount invested was Rs. 12000 |
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