A sum becomes 4 times at simple interest in 10 years. What is the rate of interest?
A. 10%
B. 20%
C. 30%
D. 40%
Answer: Option C
Solution(By Examveda Team)
$$\eqalign{ & {1^{{\text{st}}}}\,{\text{Method}}: \cr & {\text{Let rate is }}R\% \cr & {\text{Now}}, \cr & P = 100, \cr & A = 400, \cr & I = 400 - 100 = 300, \cr & {\text{Time}},\,T = 10\,{\text{years}} \cr & I = \frac{{PTR}}{{100}} \cr & {\text{Or}},R = \frac{{ {100 \times I} }}{{PT}} \cr & {\text{Or}},R = \frac{{ {100 \times 300} }}{{ {100 \times 10} }} \cr & {\text{Hence}},{\kern 1pt} R = 30\% \cr} $$2nd Method :
Here, the sum become 4 times that means 100, become 400.
Rate of such question is given by
$$R = \frac{{{\text{interest}}}}{{{\text{time}}}} = \frac{{300}}{{10}} = 30\% $$
3rd Method :
Here, 300% of rise in the sum so
$$\eqalign{ & 100 - - - 300\% \uparrow - - - {\kern 1pt} 400; \cr & R = {\frac{{{\text{total}}\,{\text{percentage rise}}}}{{{\text{given time}}}}} \cr & \,\,\,\,\,\,\,\, = \frac{{300\% }}{{10}} \cr & \,\,\,\,\,\,\,\, = 30\% \cr} $$
Related Questions on Interest
Find the simple interest on Rs. 5200 for 2 years at 6% per annum.
A. Rs. 450
B. Rs. 524
C. Rs. 600
D. Rs. 624
Rs. 1200 is lent out at 5% per annum simple interest for 3 years. Find the amount after 3 years.
A. Rs. 1380
B. Rs. 1290
C. Rs. 1470
D. Rs.1200
E. Rs. 1240
Interest obtained on a sum of Rs. 5000 for 3 years is Rs. 1500. Find the rate percent.
A. 8%
B. 9%
C. 10%
D. 11%
E. 12%
Rs. 2100 is lent at compound interest of 5% per annum for 2 years. Find the amount after two years.
A. Rs. 2300
B. Rs. 2315.25
C. Rs. 2310
D. Rs. 2320
E. None of these
Join The Discussion