📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!
  • google app store apple app store
    • ✖

      Question

      The compound interest received on investing Rs. 10,000

      for 2 years at 'y'% p.a., compounded annually is Rs. 3,689. The simple interest earned on investing Rs. 'K' for 2 years at (y + 3)% p.a. is Rs. 181 more than the compound interest received on investing Rs. (K + 400) for 2 years at (y − 2)% p.a., compounded annually. Find the value of 'K'. 
      A 3600 Correct Answer Incorrect Answer
      B 4200 Correct Answer Incorrect Answer
      C 4000 Correct Answer Incorrect Answer
      D 4400 Correct Answer Incorrect Answer
      E 3800 Correct Answer Incorrect Answer

      Solution

      Compound interest received on investing Rs. 10,000
      = Rs. [10000 × {1 + (y/100)}2 − 10000]
      So, [10000 × {1 + (y/100)} 2 − 10000] = 3689
      Or, 10000 × {(100 + y)/100}2 = 10000 + 3689 = 13689
      Or, {(100 + y)/100}2 = 13689 ÷ 10000 = 1.3689
      So, {(100 + y)/100} = √1.3689 = 1.17
      So, 100 + y = 117
      So, y = 17
      Simple interest received on investing Rs. 'K'   = K × (17 + 3) × 2 ÷ 100 = Rs. 0.4K
      Compound interest received on investing Rs. (K + 400)
      = (K + 400) × {1 + (15/100)}2 − (K + 400)
      = (K + 400) × 1.3225 − (K + 400)
      = Rs. (0.3225K + 129)
      According to the question,
      0.4K = (0.3225K + 129) + 181
      Or, 0.0775K = 310
      So, K = 310 ÷ 0.0775 = 4000

      Practice Next
      More Simple and compound interest Questions

      Relevant for Exams:

      ask-question