Let the principal be Rs. P and the rate be R% per annum

Since it doubles in 12 years.

So, simple interest is Rs. P

12R = 100

%

Hence, rate = % per annum

A) Rs. 500 | B) Rs. 245 |

C) Rs. 1250 | D) Rs. 635 |

Explanation:

(kx5x1)/100 + [(1500 - k)x6x1]/100 = 85

5k/100 + 90 – 6k/100 = 85

k/100 = 5

=> k = 500

A) Rs. 300 | B) Rs. 400 |

C) Rs. 1200 | D) Rs. 1100 |

Explanation:

Let Althaf lent Rs. A at 14% per year.

Hence, Money lent at 12% = (1500-A);

Given, total interest = Rs. 186.

{(A x 14x 1)/100} + {[(1500-A) x 12 x 1/100]} = 186;

14A/100 + (18000 -12A)/100 = 186;

14A + 18000 - 12A = 186x100;

2A = 18600-18000;

A = 600/2 = Rs. 300.

Hence, money lent at 12% = 1500-300 = Rs. 1200.

A) 7.85 % | B) 9.41% |

C) 6.66 % | D) 4.21 % |

Explanation:

Let the principle be Rs. P

As the amount double itself the interest is Rs. P too

So P = P x r x 15/100

=> r = 100/15 = 20/3 % = 6.66 %.

A) Rs. 1800 | B) Rs. 2000 |

C) Rs. 1400 | D) Rs. 1250 |

Explanation:

2500 in 5th year and 3000 in 7th year

So in between 2 years Rs. 500 is increased => for a year 500/2 = 250

So, per year it is increasing Rs.250 then in 5 years => 250 x 5 = 1250

Hence, the initial amount must be 2500 - 1250 = Rs. 1250

A) 13.33 % | B) 14.25 % |

C) 16.98 % | D) 18.75 % |

Explanation:

Given,

S.I = 3 Principal Amount

=> 3A = A x 16 x R/100

By solving, we get

=> R = 18.75%