Q17 of 52 Page 112

If simple interest and compound interest of a certain sum of money for two years are ₹8400 and ₹8652, then let us write by calculating the sum of money and the rate of interest.

Let the principal = ₹p and the rate of interest per annum = r%


∴ The interest for 2 years at the rate of simple interest r% per annum



Again the amount at the rate of compound interest r% per annum for 2 years


∴ Compound interest for 2 years




By the condition, … (1)


… (2)


Dividing equation (2) by (1),





⇒ r = 206 – 200


∴ r = 6


From (1),






∴ p = 70000


∴ Principal is ₹70000 and rate of interest is 6%.


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