Question

19. Manoj borrowed from Ramesh certain sum for 2 years at S.I. Manoj lent this sum to
Mahesh at the same rate for 2 years C.I. At the end of 2 years he received Rs. 110 as C.I.
but paid Rs. 100 as S.I. Find the sum and rate of interest.​

Answer 1

Answer:

4000, 5%

Step-by-step explanation:

Let the sum borrowed by Mahesh be RS P and rate of interest be R%p.a

Simple interest (SI)=Rs 400,N=2 years

SI=

100

P×N×R

∴P= N×R SI×100 =

2×R

400×100

∴P=

R

20000

.......... (1)

Mahesh lent this sum to vishnu at the same rate for 2 years at compound interest

CI=RS 410,N=2 years

∴CI=P(1+

100

R

)

N

−P

∴CI=P[(1+

100

R

)

N

−1]

∴410=

R

20000

[(

100

100+R

)

2

−1] .......... [From (1)]

∴410=

R

20000

[

10000

10000+R

2

+200R−10000

]

∴

20000

410×R

=

10000

R

2

+200R

∴

20000

410×R

=

10000

R(R+200)

∴

20000

410×10000

=R+200

∴205=R+200

∴R=205−200

∴R=5%pa

P=

5

20000

=Rs 4000

∴ The sum borrowed by Mahesh =Rs 4000

and rate of interest +5%pa

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