Q. 11

# Let us write by calculating the difference between compound interest and simple interest on ₹10,000 for 3 years at 5% per annum.

Answer :

Let principal = ₹x

∴ Simple interest at 5% for 3 years

= ₹0.15x

At the rate of 5% compound interest per the annum the amount for 3 years

= ₹1.157x

∴ Compound interest for 3 years = 1.157x – x = 0.157x

By the condition, 0.157x – 0.15x = 10000

⇒ 0.007x = 10000

∴ x = 1428571.42

∴ Principal is ₹1428571.42

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