Question

The interest on a certain deposit at 5% per annum is rs. 101.20 in one year. how much will the additional interest in one year be on the same deposit at 6% per annum?

Answer 1

Principal, P = 

100×SI

RT

=

100×101.20

5×1

=20×101.20=Rs. 2024

Simple Interest for Rs.2024 at 6% per annum for 1 year, SI = 

2024×6×1

100

=121.44

Principal, P = 100×SIRT=100×101.205×1=20×101.20=Rs. 2024Simple Interest for Rs.2024 at 6% per annum for 1 year, SI = 2024×6×1100=121.44



Additional Interest = Rs.121.44 - Rs.101.20 = Rs.20.24

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Solution 2
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Principal, P = 

100×SI

RT

=

100×101.20

5×1

=20×101.20=Rs. 2024

Principal, P = 100×SIRT=100×101.205×1=20×101.20=Rs. 2024



All parameters remains same except the increase in interest rate.

and additional Interest Rate = 6% - 5% = 1%

Hence, Additional Interest = Simple Interest for Rs.2024 at 1% per annum for 1 year

=

2024×1×1

100=20.24

Hence, Additional Interest = Simple Interest for Rs.2024 at 1% per annum for 1 year=2024×1×1100=20.24