**Simple Interest** Aptitude Questions and Answers – Formulas & Tricks

**Principal:** The Money borrowed or lent out for a certain period is called Principal or the Sum.

**Interest**: Extra money paid for using other’s money is called interest.

**Simple Interest:** If the interest on a sum borrowed is reckoned uniformly, then it is called Simple Interest.

- Simple Interest (SI)= (P * R * T) / 100
- Principal (P) = (100 * SI) / (R * T)
- Rate (R) = (100 * SI) / (P * T)
- Time (T) = (100 * SI) / (P * R)
- Amount (A) = P + SI => P + (P * R * T) / 100
- If a certain sum of money becomes n times itself at R% p.a simple interest, then the time T’ in which it will become m times itself is given by T’ = (m – 1 / n – 1) * T years
- If a certain sum of money P lent out at SI amounts to A
_{1}in T_{1}Years to A_{2}in T_{2}Years, then- P = (A
_{1}T_{2}– A_{2}T_{1}) / (T_{2}– T_{1}) - R = (A
_{1}– A_{2}) / (A_{1}T_{2}– A_{2}T_{1}) * 100%

- P = (A
- If a certain sum of money P lent out for a certain time T amounts to A
_{1}at R_{1}% Per annum and to A_{2}at R_{2}% Per annum, then- P = (A
_{2}R_{1}– A_{1}R_{2}) / (R_{1}– R_{2}), - T = (A
_{1}– A_{2}) / (A_{2}R_{1}– A_{1}R_{2}) * 100 years

- P = (A

Simple Interest Aptitude Questions and Answers With Detailed Explanation – Quantitative Aptitude

## Simple Interest

Question 1 |

How much Simple Interest can a person get on Rs. 8,200 at 17.5% p.a. for a period of 2 years and 6 months?

Rs. 2,850 | |

Rs. 3,587.50 | |

Rs. 3,750 | |

Rs. 3,770.50 |

Question 1 Explanation:

**Answer: Option B**

__Explanation:__

SI = (8200 * 2.5 * 17.5)/100

=(8200 * 5 * 35)/(100 * 2 * 2)

**SI = Rs. 3587.50**

Question 2 |

A sum fetched a total simple interest of Rs. 4016.25 at the rate of 9 p.c.p.a in 5 Years. What is the sum?

Rs. 8, 725 | |

Rs. 8, 825 | |

Rs. 8, 875 | |

Rs. 8, 925 |

Question 2 Explanation:

**Answer: Option D**

__Explanation:__

Principal = Rs. (100 * 4016.25)/ (9 * 5)

=Rs. 401625 / 45

**Principal = Rs. 8, 925**

Question 3 |

In 30 years an amount becomes 5 times the original amount. What is the rate of interest?

6.67% | |

12.5% | |

13.33% | |

24% |

Question 3 Explanation:

**Answer: Option C**

__Explanation:__

Original Amount = p

In T= 30 years, Amount = 5p

Therefore, Interest received in 30 years = 5p - p = 4p

Simple Interest = (PRT / 100)

4p = (p * r * 30) / 100

Therefore,

**R = 13.33%**

Question 4 |

If Rs. 460 amount to Rs. 640 in 6 years, What will it amount to in 2 years at the same rate %?

Rs. 520 | |

Rs. 585 | |

Rs. 700 | |

Rs. 640 |

Question 4 Explanation:

**Answer: Option A**

__Explanation:__

Interest for 6 years = 640 - 460 = Rs. 180

Interest for 2 years =(180/6) * 2 = Rs. 60

Therefore, 460 will become 460 + 60 = Rs. 520 after 2 years.

Question 5 |

The simple interest on a sum of money is of the principal and the number of years is equal to the rate % p.a. The rate % p.a. is

5% | |

6% | |

10% | |

9% |

Question 5 Explanation:

**Answer: Option A**

__Explanation:__

P/4 = (P * R * R)/100 -> R

^{2}= 25% -> R = 5%

Question 6 |

How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of Simple Interest?

3.5 years | |

4 years | |

4.5 years | |

5 years |

Question 6 Explanation:

**Answer: Option B**

__Explanation:__

Time = (100 * 81) / (450 * 4.5) Years = 4 years

Question 7 |

What will be the ratio of Simple Interest earned by certain amount at the same rate of interest for 6 years and that for 9 years?

1 : 3 | |

1 : 4 | |

2 : 3 | |

2 : 5 |

Question 7 Explanation:

**Answer: Option C**

__Explanation:__

Let the principal be p and rate of interest be R%

Therefore, Required Ratio =

= (6PR) / (9PR) = 6 / 9

**Required Ratio = 2 : 3**

Question 8 |

Abha took a loan of Rs. 1200 with simple interest for a many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, What was the rate of interest?

3% | |

6% | |

9% | |

12% |

Question 8 Explanation:

**Answer: Option B**

__Explanation:__

Let rate = R% and time = R years

Then, (1200 * R *R)/100 = 432

=> 12R^2 = 432

=>R^2 = 36

**R = 6**

Question 9 |

A sum was put at simple interest at a certain rate for 10 years. Had it been put at 5% higher rate, it would have fetched Rs. 600 more. What was the Sum?

Rs. 1200 | |

Rs. 1300 | |

Rs. 1400 | |

Rs. 1500 |

Question 9 Explanation:

**Answer: Option A**

__Explanation:__

At 5% more rate, the increase in SI for 10 years = Rs. 600(given)

So, at 5% more rate, the increase in SI for year = 600/10 = Rs. 60/-

That is, Rs.60 is 5% of the invested sum

So, 1% of the invested sum = 60/5

Therefore, the invested sum = 60 * (100/5) = Rs. 1200

Question 10 |

The simple interest on Rs. 25 for 4 months at the rate of 3 paisa per rupee per month is:

240 paise | |

Rs. 1.40 | |

Rs. 2.20 | |

Rs. 3 |

Question 10 Explanation:

**Answer: Option D**

__Explanation:__

I = (PTR) / 100

I = (25 * 4 * 0.03) / 100

I = 0.03 * 100 = 300ps

**I = Rs. 3**

There are 10 questions to complete.