# The C.I. on a certain sum for 2 years is Rs.410 and S.I. is Rs.400. The rate of interest per annum is ______________.

Dear Student!

Let the sum of money be Rs P and rate of interest be r  % p.a.

S.I. on the sum of money, Rs P for  2 year  C.I on the given sum of money, Rs P for 2 years Dividing (1) by (2), we get Thus, the rate of interest is 5% p.a.

Cheers!

• 7

ANS: the SI for certain sum of money for two years =Rs 400.

The SI for one year is 400/2 = Rs200

The interest for Rs 200 for one year  will be  Rs 410 -  Rs 400 = Rs10 { Since the interest for the first year is added to the principal for calculating Compound  interst for second year}

Since , at the end of 1st year the SI and the CI is same, so interest in both cases is Rs 200 each

So on Rs 200 for 1year the interest is Rs 410 - 400 = Rs10

SI = PRT/100

=> 10 = 200*R.*1/100   { principal =200, Time = 1 year , interest = Rs10}

=>R =  10 *100 /200 = 5

Therefore, rate of intererest = 5%

• 10

thanks a lot.

• -7

is there any other method to do it?

• -7

the SI for certain sum of money for two years =Rs 400.

The SI for one year is 400/2 = Rs200

The interest for Rs 200 for one year  will be  Rs 410 -  Rs 400 = Rs10 { Since the interest for the first year is added to the principal for calculating Compound  interst for second year}

Since , at the end of 1st year the SI and the CI is same, so interest in both cases is Rs 200 each

So on Rs 200 for 1year the interest is Rs 410 - 400 = Rs10

SI = PRT/100

=> 10 = 200*R.*1/100   { principal =200, Time = 1 year , interest = Rs10}

=>R =  10 *100 /200 = 5

• 0
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