Tag: introduction to interest

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Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

The time required so that Rs 450 may increase to Rs 576 (the rate of simple interest being 7% per annum) is

  1. 2 years

  2. 3 years

  3. 4 years

  4. 6 years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple interest will be(576-450)=Rs126

 Let the Time required  be t
As per formula,
$Simple\quad Interest=\frac { P\times t\times r }{ 100 } $
$126=\frac { 450\times t\times 7 }{ 100 } $
$315t=1260$
$t=\frac { 1260 }{ 315 } =4$
Time required will be 4 years


Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

If the simple interest on a certain sum of money is $\displaystyle \frac{4}{25}$th of the sum and the rate per cent equals the number of years, then the rate of interest per annum is

  1. $2$%
  2. $4$%
  3. $5$%
  4. $6$%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\Rightarrow$   Let the principal be $Rs.x$.

$\Rightarrow$   Then, Simple Interest = $\dfrac{4}{25}x.$
$\Rightarrow$    Let the rate of interest per annum be $r\%$ then time ( T)= $r$ years.
$\Rightarrow$   $R=\dfrac{100\times S.I.}{P\times T}$

$\Rightarrow$   $r=\dfrac{100\times \dfrac {4x}{25}}{x\times r}$

$\Rightarrow$   $r^2=\dfrac{400}{25}$

$\Rightarrow$   $r=\dfrac{20}{5}=4\%$

Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

John earned Rs. $100$ as simple interest on Rs. $600$ for $6$ months. Find the annual rate of interest.

  1. $11.11\%$
  2. $32.11\%$
  3. $33.33\%$
  4. $30\%$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Here, $S.I.=$ Rs. $100,\,P=$ Rs. $600$ and $T=6$ months $=\dfrac{1}{2}$ year

We know $S.I.=\dfrac{P\times R\times T}{100}$
$\Rightarrow$ $100=\dfrac{600\times R\times 1}{2\times 100}$
$\Rightarrow$ $R=\dfrac{20000}{600}$
$\Rightarrow$ $R=33.33\%$

Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

You invested Rs. $1500$ and received Rs. $5000$ after three years. What had been the interest rate?

  1. $111.11\%$
  2. $222.22\%$
  3. $99.99\%$
  4. $77.77\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Here, $P=$ Rs. $1500\,A=$ Rs. $5000$ and $T=3$ years
$\Rightarrow$ $S.I=A-P=$ Rs. $5000-$ Rs. $1500=$ Rs. $3500$
$\Rightarrow$ $S.I.=\dfrac{P\times R\times T}{100}$
$\Rightarrow$ $3500=\dfrac{1500\times R\times 3}{100}$
$\Rightarrow$ $R=\dfrac{3500\times 100}{4500}$
Therefore, $R=77.77\%$
Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

What rate will amount to Rs. $33,080$ in three years, if the principle amount was Rs $10,000$ respectively?

  1. $48$%
  2. $49$%
  3. $50$%
  4. $12$%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$A=P(1+\cfrac{r}{100})^n$
$\implies 33,080=10,000[(1+\cfrac{r}{100})^3-1]\\ \implies 1+\cfrac{r}{100}=(33080/10000)^{1/3}\\ \implies r=49$.
Hence rate of intererst is $49\%$ per annum.
Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

Find rate, when principal = Rs. $30,000$; interest = Rs. $900$; time = $3$ years.

  1. $1$%
  2. $2$%
  3. $4$%
  4. $5$%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Under simple interest,


Interest $= Principal \times rate \times time$

Principal $=$ Rs. $30000$
Rate $= r$
Time $= 3$ years
Interest $=$ Rs. $900$

$\Rightarrow 900 = 30000 \times r \times 3$
$\therefore r = 0.01$ or $1\%$

Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

At which percent per annum simple interest will double a sum of money in 12 years?

  1. $8\dfrac { 1 }{ 3 }\%$
  2. $24\%$
  3. $\dfrac { 25 }{ 4 }\%$
  4. $8.25\%$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let,

Principle P = 100
Amount A = 200
Time T = 12 years
Interest = Rs. 100
Rate of Interest = $\dfrac{(Interest)}{Time}$ = $\dfrac{100}{12}$ = $\dfrac{25}{3}$ = 8$\dfrac{1}{3}$%
Option A is correct

Multiple choice mathematics and statistics banks and simple interest introduction to interests introduction to interest introduction to interest payments

A man invests half his capital at the rate of l0% per annum, one-third at 9% and the rest at 12% per annum. The average rate of interest per annum which he gets, is

  1. 9%

  2. 10%

  3. 10.5%

  4. 12%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using the rule of weighted average,
The average rate of interest = $\displaystyle \dfrac{\dfrac{1}{2} \, \times \, 10 \, + \, \dfrac{1}{3} \, \times \, 9 \, + \, \dfrac{1}{6} \, \times \, 12}{\dfrac{1}{2} \, + \, \dfrac{1}{3} \, + \,\dfrac{1}{6}}$
= 5 + 3 + 2 = 10%