Quantitative Aptitude Ques 507
Question: A certain amount of money earns Rs. 540 as simple interest in 3 yr. If it earns a compound interest of Rs. 376.20 at the same rate of interest in 2 yr, then find the amount.
Options:
A) Rs. 1600
B) Rs. 2000
C) Rs. 1800
D) Rs. 2100
Show Answer
Answer:
Correct Answer: B
Solution:
- [b] Here, SI =540 and t = 3 yr
$ \therefore $ $ \frac{P\times 3\times r}{100}=540 $
$ \Rightarrow $ $ r=\frac{540\times 100}{3P}=\frac{18000}{P} $
Now, CI = 376.20 and t = 2 yr
$ \Rightarrow $ 376.20 $ =P[ {{( 1+\frac{18000}{100P} )}^{2}}-1 ]=P[ {{( 1+\frac{180}{P} )}^{2}}-1 ] $ $ =P[ \frac{P^{2}+32400+360P-P^{2}}{P^{2}} ] $ $ 376.20=\frac{32400+360P}{P} $
$ \Rightarrow $ $ ,376.20P=32400+360P $
$ \Rightarrow $ $ 16.20P=32400 $
$ \Rightarrow $ $ P=Rs.2000 $
BETA
