Question

how many years will be required to double principal amount of rs. 5000 by simple interest at the rate of 4 p.c.p.a.?

Answer 1

Step-by-step explanation:

Solve it by self by putting values

And Plzzz like it

Answer 2

The amount returned by the deposition or withdrawal of the principal amount $\displaystyle\sf {P_0}$ after $\displaystyle\sf {n}$ years by simple interest at a rate of $\displaystyle\sf {r}$ percent per annum is,

$\displaystyle\longrightarrow\sf {P_n=P_0+\dfrac {P_0nr}{100}}$

$\displaystyle\longrightarrow\sf {P_n=P_0\left [1+\dfrac {nr}{100}\right]}$

But if $\displaystyle\sf {P_n=k\cdot P_0,}$ then,

$\displaystyle\longrightarrow\sf {k\cdot P_0=P_0\left [1+\dfrac {nr}{100}\right]}$

$\displaystyle\longrightarrow\sf {1+\dfrac {nr}{100}=k}$

$\displaystyle\longrightarrow\sf {\dfrac {nr}{100}=k-1}$

$\displaystyle\longrightarrow\sf {\underline {\underline {nr=100(k-1)}}}$

Nice relation, right?! This equation can be used even if no principal amount is given!

Here,

• $\displaystyle\sf {r=4}$

• $\displaystyle\sf {k=2}$

Then,

$\displaystyle\longrightarrow\sf {4n=100(2-1)}$

$\displaystyle\longrightarrow\sf {4n=100}$

$\displaystyle\longrightarrow\sf {\underline {\underline {n=25}}}$

Hence 25 years are required to double the principal amount.