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A sum of money invested at simple interest becomes 13/10 of itself in 2 years and 6 months. What is the rate (in percentage) of interest per annum?
- A10
- B15
- C12
- D18
Answer not set
Discussion 1
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CCommunity
Let the sum of money invested be a and rate of interest be r
Time of investment = 2 years 6 months = 2.5 years
Simple interest = (Principle × time × rate)/100 = (a × r × 2.5)/100 = ar/40
According to the question,
Amount = (13/10) × Sum of money invested
⇒ (ar/40) + a = (13/10) × a
⇒ (r + 40)/40 = 13/10
⇒ r + 40 = 52
∴ r = 12%
Time of investment = 2 years 6 months = 2.5 years
Simple interest = (Principle × time × rate)/100 = (a × r × 2.5)/100 = ar/40
According to the question,
Amount = (13/10) × Sum of money invested
⇒ (ar/40) + a = (13/10) × a
⇒ (r + 40)/40 = 13/10
⇒ r + 40 = 52
∴ r = 12%