Question

plzzzzzzzzzz do it....​

Answer 1

$\sf\large\underline\purple{Given:-}$

$\sf{\implies Principal=Rs.30000}$

$\sf{\implies Rate=8\%}$

$\sf{\implies Simple\:interest=Rs.2400}$

$\sf\large\underline\purple{To\: Find:-}$

$\sf{\implies Time\:_{(for\: simple\: interest)}=?}$

$\sf{\implies CI\:_{(for\: compound\: interest)}=?}$

$\sf\large\underline\purple{Solution:-}$

To calculate compound interest at first we have to find out time for simple interest by applying formula of SI then calculate compound interest. As given in the question that in compound interest the time is given in half yearly so, we have to change time and rate. For changing time we have to multiply by 2 and for rate dividing by 2:-]

$\sf\small\underline\green{Calculation\:for\:SI:-}$

$\sf\small\underline{Here,\:\:P=30000\:\:R=8\%\:\:SI=2400:-}$

$\tt{\implies SI=\dfrac{P\times\:T\times\:R}{100}}$

$\tt{\implies 2400=\dfrac{30000\times\:T\times\:8}{100}}$

$\tt{\implies 2400=300\times\:T\times\:8}$

$\tt{\implies 2400=2400T}$

$\tt\pink{\implies T=1\: year}$

$\sf\small\underline\green{Calculation\:for\:CI:-}$

$\sf\small\underline{Here,\:\:P=30000\:\:R=8/2=4\%\:\:T=1*2=2\: years:-}$

$\tt{\implies CI=P\bigg(1+\dfrac{r}{100}\bigg)^{n}-P}$

$\tt{\implies CI=30000\bigg(1+\dfrac{8}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\bigg(\dfrac{100+8}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\bigg(\dfrac{108}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\times\:(1.08)^{2}-30000}$

$\tt{\implies CI=30000\times\:1.1664-30000}$

$\tt{\implies CI=34992-30000}$

$\tt\pink{\implies CI=Rs.4992}$

$\sf\large{Hence,}$:-

$\sf\blue{\implies Time\:_{(for\: simple\: interest)}=1\: year}$

$\sf\blue{\implies CI\:_{(for\: compound\: interest)}=Rs.4992}$

Answer 2

$\sf\large\underline\pink{Given:-}$

$\sf{\implies Principal=Rs.30000}$

$\sf{\implies Rate=8\%}$

$\sf{\implies Simple\:interest=Rs.2400}$

$\sf\large\underline\purple{To\: Find:-}$

$\sf{\implies Time\:_{(for\: simple\: interest)}=?}$

$\sf{\implies CI\:_{(for\: compound\: interest)}=?}$

$\sf\large\underline\purple{Solution:-}$

To calculate compound interest at first we have to find out time for simple interest by applying formula of SI then calculate compound interest. As given in the question that in compound interest the time is given in half yearly so, we have to change time and rate. For changing time we have to multiply by 2 and for rate dividing by 2:-]

$\sf\small\underline\red{Calculation\:for\:SI:-}$

$\sf\small\underline{Here,\:\:P=30000\:\:R=8\%\:\:SI=2400:-}$

$\tt{\implies SI=\dfrac{P\times\:T\times\:R}{100}}$

$\tt{\implies 2400=\dfrac{30000\times\:T\times\:8}{100}}$

$\tt{\implies 2400=300\times\:T\times\:8}$

$\tt{\implies 2400=2400T}$

$\tt\pink{\implies T=1\: year}$

$\sf\small\underline\orange{Calculation\:for\:CI:-}$

$\sf\small\underline{Here,\:\:P=30000\:\:R=8/2=4\%\:\:T=1*2=2\: years:-}$

$\tt{\implies CI=P\bigg(1+\dfrac{r}{100}\bigg)^{n}-P}$

$\tt{\implies CI=30000\bigg(1+\dfrac{8}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\bigg(\dfrac{100+8}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\bigg(\dfrac{108}{100}\bigg)^{2}-30000}$

$\tt{\implies CI=30000\times\:(1.08)^{2}-30000}$

$\tt{\implies CI=30000\times\:1.1664-30000}$

$\tt{\implies CI=34992-30000}$

$\tt\red{\implies CI=Rs.4992}$

$\sf\large{Hence,}$:-

$\sf\blue{\implies Time\:_{(for\: simple\: interest)}=1\: year}$

$\sf\green{\implies CI\:_{(for\: compound\: interest)}=Rs.4992}$