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The difference between the compound interest for a year payable half-yearly and the simple interest on a certain sum of money lent out at 10% for a year is rupees 15 find the compound interest. |
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Answer»
LET the principal, P = Rs.x, r = 10%, t = 1 year
Using S.I. = Prt/100, S.I. = Rs.(x × 10 × 1)/100 =Rs.x/10
No of conversion PERIOD, n = 2 × 1 = 2, r = 10%/2 = 5% per conversion period, P = x,
Using C.I. = P [(1 + r/100)n 1], C.I. = Rs.x [(1 + 5/100)2 1] = Rs.x(21/20 ×21/20 1) = Rs.x(441/400 1) = Rs.(41/400)x As per problem, C.I. S.I. = Rs.180 Or, Rs.(41/400)x Rs.x/10 = 180 Or, Rs.(41/400 1/10)x = 180 Or, Rs.x/400 = 180 Or, x = Rs.180 × 400 = Rs.7200 |
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