Quantitative Aptitude Ques 554

Question: 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]

Options:

A) Rs. 10000

B) Rs. 6000

C) Rs. 12000

D) Rs. 8000

E) None of these

Show Answer

Answer:

Correct Answer: D

Solution:

  • Let the sum of money be Rs. x. According to the question, $ ( x{{( 1+\frac{5}{100} )}^{4}}-x )-( \frac{x\times 20}{100} )=124.05 $

$ \Rightarrow $ $ x{{( \frac{21}{20} )}^{4}}-x-\frac{x}{5}=124.05 $

$ \Rightarrow $ $ x( \frac{441\times 441}{16\times 10^{4}} )-\frac{6x}{5}=124.05 $

$ \Rightarrow $ $ x( \frac{194481-192000}{160000} )=124.05 $

$ \Rightarrow $ $ x=\frac{124.05\times 160000}{2481} $
$ \Rightarrow $ $ x=Rs.,8000 $