# Simple Interest Questions

**FACTS AND FORMULAE FOR SIMPLE INTEREST QUESTIONS**

**1. Principal:** The money borrowed or lent out for a certain period is called the **principal **or the **sum**.

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

**3. Simple Interest (S.I.) : **If the interest on a sum borrowed for a certain period is reckoned uniformly, then it is called **simple interest.**

Let Principal = P, Rate = R% per annum (p.a.) and Time = T years. Then,

(i) $S.I=\left(\frac{P\times T\times R}{100}\right)$

(ii) $P=\left(\frac{100\times S.I}{R\times T}\right);R=\left(\frac{100\times S.I}{P\times T}\right)andT=\left(\frac{100\times S.I}{P\times R}\right)$

A) 240 paise | B) Rs. 1.40 |

C) Rs. 2.20 | D) Rs. 3 |

Explanation:

I = PTR/100

I = 25 x 4 x 0.03/100

I = 0.03 x 100 = 300 Ps = Rs. 3

A) I and III only | B) II and III only |

C) I and II only | D) Any two of the three |

Explanation:

Clearly, any of the three will give us the answer

A) Rs.1625 | B) Rs1525 |

C) Rs.1425 | D) Rs.1325 |

Explanation:

Let sum be Rs.x then, S.I. =Rs. [ x * (27/2) * 4 * (1/100) ] = Rs. 27x/50

Amount =Rs [ x + (27x/50)] = Rs.77x/50

=> 77X/50 = 2502.50

=>X= (2502.50 * 50)/77 = 1625

Hence Sum = Rs.1625

A) 1:3 | B) 1:4 |

C) 2:3 | D) data is inadequate |

Explanation:

Let the principal be P and rate of interest be R%.

Required ratio =$\left[\left(\frac{{\displaystyle \raisebox{1ex}{$P*R*6$}\!\left/ \!\raisebox{-1ex}{$100$}\right.}}{{\displaystyle \raisebox{1ex}{$P*R*9$}\!\left/ \!\raisebox{-1ex}{$100$}\right.}}\right)\right]=\frac{6PR}{9PR}=\frac{6}{9}=\frac{2}{3}$

A) Rs. 1100 | B) Rs. 1200 |

C) Rs. 1000 | D) Rs. 1840 |

Explanation:

P --- 10 ----- 600

P --- 5 ----- 300

3P --- 5 ----- 900

__________

1200

A) 0.3 Paise | B) 1.2 Paise |

C) 30 Paise | D) 3 Paise |

Explanation:

Given Principal amount P = Rs. 10

Time T = 4 months

Rate of interest R = 3 ps

Interest **I = PTR/100 = (10 x 4 x 3)/100 = 12/10** =** 1.2 paise.**

A) I alone sufficient while II alone not sufficient to answer | B) II alone sufficient while I alone not sufficient to answer |

C) Either I or II alone sufficient to answer | D) Both I and II are necessary to answer |

Explanation:

Given : S.I. = Rs. 50.

I gives, R = 10% p.a.

II gives, T = 10 years.

Sum = (100 x S.I)/(t x r ) = Rs.(100 x 50)/(10 x 10) = Rs.50

A) 3.5 years | B) 4 years |

C) 4.5 years | D) 5 years |