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A certain sum of money amounts to Rs. 5320 in 3 years at simple interest and to Rs. 5980 in 4 years and 6 months at simple interest. Find the rate of interest.
- A10 percent
- B11 percent
- C12 percent
- D13 percent
Answer not set
Discussion 1
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CCommunity
⇒ Amount for 3 years = Rs. 5320
⇒ Amount for 4 years and 6 months = Rs. 5980
⇒ So interest for 1 year 6 months = Rs. 660
⇒ Interest for 1 years = 660 × 2/3
⇒ So interest for 3 years = 1320
⇒ P = A for 3 years – Interest for 3 years = 5320 – 1320 = 4000
∴ R = SI × 100/P × T = (1320 × 100)/(4000 × 3) = 11%
⇒ Amount for 4 years and 6 months = Rs. 5980
⇒ So interest for 1 year 6 months = Rs. 660
⇒ Interest for 1 years = 660 × 2/3
⇒ So interest for 3 years = 1320
⇒ P = A for 3 years – Interest for 3 years = 5320 – 1320 = 4000
∴ R = SI × 100/P × T = (1320 × 100)/(4000 × 3) = 11%