Question

if a sum of 1000 rupees was loaned in the year 1940, what is the value of that 1000 rupees in the year 2021 at 10% interest , how do I calculated it, what is the formula?​

Answer 1

Given:

• if a sum of 1000 rupees was loaned in the year 1940

To Find:

• what is the value of that 1000 rupees in the year 2021 at 10%

Solution:

★ As per the above mentioned statement we have to find the intrest on the money (rupees 1000)

● here,

➱ Let's apply for the formula to find the simple interest on the money for a period of time on a certain amount of money and add it to the initial money to find the value of it at present!

➼ Formula :-

${ \pink{ \boxed{ \tt{ simple \: intrest = \frac{p \times r \times t}{100} } }} {\pink{\star}}}$

Where,

• ↝ P Stands for principal
• ↝ T Stands for time
• ↝ R Stands for Rate

Here,

• Principal = ₹1000
• Time = 2021 - 1940 = 81 years
• Rate of interest = 10% (per annmun)

Putting the values,

${ : \implies} \rm \: simple \: intrest = \frac{prinipal \times time \times rate}{100} \\ \\ \\ { : \implies} \rm \: simple \: intrest = \frac{100 \cancel0 \times 81 \times 1 \cancel0}{1 \cancel0 \cancel0} \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \\ { : \implies} \rm \: simple \: intrest = 100 \times 81 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \\ { : \implies} \rm \: simple \: intrest = { \pink{ \boxed{ \tt{8100 \: rupees}} \star}} \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

• Hence the simple interest of the money is 8100 rupees!

➱Now, We have to find the amount,

➼ Formula : -

$\circ \: { \pink{ \boxed{ \rm{ \: amount = principal + intrest}}} {\pink{\star}}}$

Here,

• ↝ Principal = ₹ 1,000
• ↝ Interest = ₹ 8,100

Substituting the values

${ : \implies} \rm \: Amount = principal + intrest \\ \\ { : \implies} \rm \: Amount = 1000 + 8100 \: \: \: \: \: \: \: \: \: \: \: \\ \\ { : \implies} \rm \: Amount = { \pink{ \boxed{ \tt{9100 \: rupees}} \star}} \: \: \: \: \:$

• Henceforth the Amount is ₹ 9100

Therefore:

• The value of that 1000 rupees in the year 2021 is ₹ 9100

Additional Info:

Some related formulas :-

$\begin{gathered}\small\boxed{\begin{array}{cc}\large\sf\dag \: {\underline{More \: Formulae}} \\ \\ \bigstar \: \sf{Gain = S.P – C.P} \\ \\ \bigstar \:\sf{Loss = C.P – S.P} \\ \\ \bigstar \: \sf{Gain \: \% = \Bigg( \dfrac{Gain}{C.P} \times 100 \Bigg)\%} \\ \\ \bigstar \: \sf{loss \: \% = \Bigg( \dfrac{loss}{C.P} \times 100 \Bigg)\%} \\ \\ \bigstar \: \sf{S.P = \dfrac{100+Gain\%}{100} \times C.P} \\ \\ \bigstar \: \sf{C.P =\dfrac{100}{100+Gain\%} \times S.P} \\ \\ \bigstar \: \sf{C.P =\dfrac{100}{100-loss\%} \times S.P}\end{array}}\end{gathered}$