Q. 124.2( 26 Votes )

# Let us write by calculating the sum of money, if the difference between compound interest and simple interest for 2 years at the rate of 9% interest per annum is ₹129.60.

Answer :

Let principal = ₹x

∴ Simple interest at 9% for 2 years

= ₹0.18x

At the rate of 9% compound interest per the annum the amount for 2 years

= ₹1.1881x

∴ Compound interest for 2 years = ₹1.18x – x = 0.1881x

By the condition, 0.1881x – 0.18x = 129.60

⇒ 0.0081x = 129.60

∴ x = ₹16000

∴ Principal is ₹16000

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