Arithmetic aptitude :: Simple Interest :: General Questions

• Simple Interest - General Questions
• Simple Interest - Data Sufficiency 1
• Simple Interest - Data Sufficiency 2
• Simple Interest - Important Formulas and Facts

Principal :

The amount of money one borrows from a lender for a certain period of time is known as principal amount or the sum.

Interest :

Extra charge paid for the borrowed money is called Interest

Simple Interest (S.I.) :

Simple interest is a method to calculate the interest amount on a loan

Let Pricipal $=P$, Rate $=R\%$ per annum (p.a.) and Time $=N$ years. Then

(i) Simple interest (SI) $=\left(\frac{P\times N\times R}{100}\right)$

(ii) $P$ $=\left(\frac{100\times SI}{R\times N}\right)$ ; $R=\left(\frac{100\times SI}{P\times N}\right)$ and $N=\left(\frac{100\times SI}{P\times R}\right)$.

A certain sum of money becomes three times of itself in 20 Yrs at simple interest. In how many years does it become double of itself at the same rate of simple interest?

Answer:

Explanation:

Case I

$P=x$; $A=3x$; $I=2x$

$SI$ $=\frac{PNR}{100}$  $\Rightarrow 2x$ $=\frac{(x\times R\times 20)}{100}$

$R$ $=10\%$

Case II

$P=x$; $A=2x$ ; $I=x$; $N$ = ?

$SI$ $=\frac{PNR}{100}$ $\Rightarrow x=\frac{(x\times N\times 10)}{100}$

$N$ = 10 Yrs

Simple interest on Rs. 500 for 4 years at 6.25% per annum is equal to the simple interest on Rs. 400 at 5% per annum for a certain period of time. The period of time is

Answer:

Explanation:

Period of time be $N$

Given $\frac{(400\times 5\times N)}{100}$ $=\frac{(500\times 4\times 6.25)}{100}$

$\Rightarrow N=\frac{25}{4}$

$=6\frac{1}{4}$ Yrs

Rs. 6,000 becomes Rs. 7,200 in 4 years at a certain rate of simple interest. If the rate becomes 1.5 times of itself, the amount of the same principal in 5 years will be

Answer:

Explanation:

$SI$ $=(7200-6000)$ $=1200$

$SI$ $=\frac{PNR}{100}$

$1200$ $=\frac{(6000\times 4\times R)}{100}$

$\Rightarrow R$ $=5\%$

New rate $=5\times 1.5$ $=7.5\%$

$SI$ $=\frac{(6000\times 7.5\times 5)}{100}$ $=2250$

Amount $=6000+2250$ = Rs. 8250

Anand took some money for borrowed, for 3 years the total will be Rs. 5000 and 5 years it will be Rs. 6000/-. Then how much amount he borrowed ?

Answer:

Explanation:

$3$ years --------> Rs. $5000$

$5$ years --------> Rs. $6000$

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$2$ years ---------> Rs. $1000$

$1$ year  ----------> Rs. $500$

$3$ years $\times$ Rs. $500$ = Rs. $1500$

$P$ = Rs. $5000$ - Rs. $1500$ = Rs. $3500$

$P$ = Rs.3500/-

Ashoke borrowed some amount, after 6 years he paid Rs. 20,800/- with 10% interest, then how much Amount he borrowed ?

Answer:

Explanation:

Principal, $P$ = ?

Rate of interest, $R$ $=10\%$

Time, $T$ $=6$ years

Accumulated Amount, $A$ = Rs. $20800$/-

$A=P+I$

$A$ $=P+\frac{PTR}{100}$

$A$ $= P\left(1+\frac{TR}{100}\right)$

Rs. $20800$/- $=P\left[1+ 6\times\frac{10}{100}\right]$

Rs. $20800$/- $=P\left[\frac{1}{1} +\frac{6}{10}\right]$

Rs. $20800$/- $=P\left[10+\frac{6}{10}\right]$ $=P\left[\frac{16}{10}\right]$

Rs. $20800$/- $=P\times\frac{16}{10}$

$\Rightarrow P$ = Rs. $\frac{208000}{16}$

$\Rightarrow P$ = Rs.13000/-

• Simple Interest - General Questions
• Simple Interest - Data Sufficiency 1
• Simple Interest - Data Sufficiency 2