Question

Q21. Kelly borrowed from Richie a certain sum of money for 2 years at simple interest. Kelly lent this sum to
Rexy at the same rate for 2 years at compound interest.. At the end of 2 years Kelly received rs. 110 as
compound interest but paid Rs. 100 as simple interest. Find the sum of money and the rate of interest.
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Answer 1

Answer:

Sum borrowed by Reena = Rs 250

Rate of Interest = 20 %

Step-by-step explanation:

Given,

Simple Interest for 2 years = Rs 100

Compound Interest for 2 years = Rs 110

Since,

S.I for 2 years = Rs 100

∴ S.I for 1 year = Rs 50

By Compound Interest,  Interest for 1 year = Rs 50

By compound Interest , Interest for 2 year = Rs ( 110 - 50 )

                                                                      = Rs 60

∴ Rate of Interest = $\frac{60-50}{50}$× 100 %

                             = 20 %

Now,

     S.I = $\frac{P*T*R}{100}$

⇒  100 = $\frac{P*2*20}{100}$

⇒ P = $\frac{100*100}{2*20}$

⇒ P = Rs 250

Therefore,

Sum borrowed = Rs 250

Rate of Interest = 20 %