Question

10. Kamala borrowed from Ratan a certain sum at a certain rate for two years simple interest
She lent this sum at the same rate to Hari for two years compound interest. At the end of tw
years she received * 210 as compound interest, but paid * 200 only as simple interest. Fin
the sum and the rate of interest.​

Answer 1

Step-by-step explanation:

Let the sum be Rs. P and the rate of intersect be R%

We know that Kamala paid Rs. 200 as simple interest

∴200=

100

PR×2

PR=10000 _______ (1)

Also, Kamala received Rs 210 as compound interest

∴210=P(1+

100

R

)

2

−1

210(1000)=P(R

2

+200R)

210R=R

2

+200R from (1)

⇒R

2

−210R+200R=0

⇒R

2

−10R=0

⇒R(R−10)=0 ∴R



=0,R=10%

put R=10 in (1) P×10=10,000

∴P=Rs.1000

Thus, the required sum is Rs 1000 and rate of interest is 10%

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