| The difference between the simple interest on a certain sum at the rate of 10% per annum for 2 yr and compound interest which is compounded every 6 months is Rs. 124.05. What is the principal sum? [SBI (PO) 2000] |
A) Rs. 10000
B) Rs. 6000
C) Rs. 12000
D) Rs. 8000
E) None of these
Correct Answer: D
Solution :
| Let the sum of money be Rs. x. |
| According to the question, |
| \[\left( x{{\left( 1+\frac{5}{100} \right)}^{4}}-x \right)-\left( \frac{x\times 20}{100} \right)=124.05\] |
| \[\Rightarrow \] \[x{{\left( \frac{21}{20} \right)}^{4}}-x-\frac{x}{5}=124.05\] |
| \[\Rightarrow \] \[x\left( \frac{441\times 441}{16\times {{10}^{4}}} \right)-\frac{6x}{5}=124.05\] |
| \[\Rightarrow \] \[x\left( \frac{194481-192000}{160000} \right)=124.05\] |
| \[\Rightarrow \] \[x=\frac{124.05\times 160000}{2481}\]\[\Rightarrow \]\[x=Rs.\,8000\] |
You need to login to perform this action.
You will be redirected in
3 sec
