Banking Operations and Interest - class-X

Current deposit type of bank account is operated by businessman.

Lump sum amount is deposited at one time for a specific period is called fixed deposit.

In saving deposit account interest is calculated half yearly on the minimum balance between $11^{th}$ and the last day of the month.

We have, Amount of money in savings account at the beginning of the month =Rs.1500
Total amount of money withdrawal Rs 1200+2100=Rs.3300
Total amount of money deposited =Rs(2000+2500)=Rs.4500
So, total amount of money after transactions=Rs (1500-3300+4500)=Rs.2700 

We know that $ SI = \dfrac {PNR}{100} $
We clearly see that when Simple Interest and the time $ N $ is constant or same, then Principal $ P $ varies inversely with $ R $
So, if $ R $ is in the ratio $ 5:4 $ then $ P $ deposited should be in the inverse $ 4: 5 $

According to the entries in the passbook:

Principal for the year 2010=Rs.24,000

According to the passbook:

Using the formula,
Saving account interest $=$ Principal or amount in the account $\times$ Number of days $\times$ Daily Interest Rate
At $2% $daily interest rate $=$ $\dfrac{2%}{365}$
$=$ $\dfrac{1200\times3\times2}{100\times365}$
$= 0.197$

Using the formula,
Saving account interest $=$ Principal or amount in the account $\times$ Number of days $\times$ Daily Interest Rate
At $2%$ daily interest rate $=$ $\dfrac{2%}{365}$
$=$ $\dfrac{100,000\times2\times2}{100\times365}$
$= 10.95$

In bank, the minimum balance From $10^{th}$ date to last day of month.

In bank gives interest on minimum balance between 10 Th to last date of month in S.B A\c

Using the formula,
Saving account interest $=$ Principal or amount in the account $\times$ Number of days $\times$ Daily Interest Rate
At $3%$ daily interest rate $=$ $\dfrac{3%}{365}$
$=$ $\dfrac{10,000,000\times20\times3}{100\times365}$
$= 1,643.83$

We know the formula,
$A = P\left (1+\dfrac{r}{n}\right)^{n.t}$
Where,
$A =$ total amount
$P =$ principal or amount of money deposited,
$r =$ annual interest rate
$n =$ number of times compounded per year
$t =$ time in years
Given: $P =$ Rs. $6500, r = 7%, n = 1$ and $t =$ $2\dfrac{1}{2}$ years
$\Rightarrow A = 6500\left (1+\dfrac{0.07}{1}\right)^{1\times 2.5}$
$\Rightarrow A = 6500\times 1.07^{2.5}$
$\Rightarrow A = 6500\times 1.184294$
$\Rightarrow A =$ Rs. $7697.91$ $\text{approx}$ $7700$

Using the formula,
Saving account interest $=$ Principal or amount in the account $\times$ Number of days $\times$ Daily Interest Rate
At $12% $ daily interest rate $=$ $\dfrac{12%}{365}$
$=$ $\dfrac{30,000,000\times30\times12}{100\times365}$
$= 295,890.411$

Given: $P = 5000, r = 12%, n = 2$ years
We know the formula $A = P\left [\left (1+\dfrac{r}{100}\right)^n\right]$
Substituting the given values int he formula, we get

Given, $P = $ Rs. $20000$, $r = 12%$, $n = 1$, $t = 2$ years
$A =$ $P\left (1+\dfrac{r}{n}\right)^{nt}$
$A =$ $20000\times (1+0.12)^{1\times 2}$
$A = 20000 \times  1.2544$
$A = Rs. 25088$
Amount $=$ Principal $+$ Interest
Interest $= A - P$
$= 25088 - 20000$
$=$ Rs. $5088$

Given, $P =$ Rs. $4500$, $r = 10%$, $n = 1$, $t = 9$ years
$A =$ $P(1+0.1)^{1.9}$
$A = 4500 \times 2.357948$
$A =$ Rs. $10610.77$
Amount $=$ Principal $+$ Interest
Interest $= A - P$
$= 10610.77 - 4500$
$=$ Rs. $6110.77$