Question

When will ₹ 1600 amount to ₹ 1764 at 5 percent C.I ?

• A. After 1 year
• B. After 3 years
• C. After 2 years
• D. After 24 months

Answer 1

Answer: (C), (D)

The correct options are
C

After 2 years

D

After 24 months

Let the time period be n.
Given A = ₹ 1764 P = ₹ 1600 R = 5 %
$A=P(1+\frac{R}{100}{)}^n$

$1764=1600(1+\frac{5}{100}{)}^n$

$\frac{1764}{1600}=(1+\frac{5}{100}{)}^n$

$\frac{1764}{1600}=(\frac{105}{100}{)}^n$
$=(\frac{21}{20}{)}^n$

$\frac{441}{400}=(\frac{21}{20}{)}^n$

$(\frac{21}{20}{)}^2=(\frac{21}{20}{)}^n$

By comnparing LHS and RHS of the given equation we get, n = 2 years or 24 months.