4
Q:

# What annual installment will discharge a debt of Rs. 1092 due in 3 years at 12% S.I?

Q:

The simple interest on a sum of money is 1/9 of the principal and the number of years is equal to the rate percent per annum. The rate percent per annum is?

Let the sum be Rs.x, then S.I = Rs. $\inline&space;\frac{x}{9}$

Let the rate be R% per annum and the time be  R years then $\inline&space;\frac{x}{9}=\frac{x\times&space;R\times&space;R}{100}$

$\inline&space;\Rightarrow&space;R=\sqrt{\frac{100}{9}}=\frac{10}{3}=3\frac{1}{3}$ %

1598
Q:

At What rate percent per annum will a sum of money double itself is 12 years?

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

$\inline&space;\therefore$ $\inline&space;P=\frac{P\times&space;R\times&space;12}{100}$

$\inline&space;\Rightarrow$ 12R = 100

$\inline&space;\Rightarrow&space;R=\frac{100}{12}=8\frac{1}{3}$ %

$\inline&space;\therefore$ Hence, rate = $\inline&space;8\frac{1}{3}$ % per annum

551
Q:

A person lends Rs. 300 to A at 4% and Rs.540 to B at 6% for the same time. if the total amount that he gets at the end is Rs. 1032. What is the time?

Money lent to A+B = (300+ 540) = Rs. 840

Interest received = Rs. 1032 - Rs.840 = Rs. 192

Interest on Rs. 300 lent to A for 1 year = $\inline&space;\frac{300\times&space;4}{100}$ = Rs. 12

Interest on Rs.540 lent to B for 1 year = $\inline&space;\frac{540\times&space;20}{3\times&space;100}$ = Rs. 36

$\inline&space;\therefore$ Total yearly interest = Rs.(12+36)

= Rs.48

If interest is Rs. 48, time = 1 year

if interest is Rs. 192, time = $\inline&space;\frac{1}{48}\times&space;192$

= 4 years

460
Q:

Mohan borrowed a sum of Rs. 12000 at 15% per annum from a money -lender on 13th January 1987 and returned the amount on 8th June 1987 to clear his debt. what was the amount by Mohan to the money-lender to clear his debt?

Here P= Rs. 12,000 , R= 15%

T = Money kept for the No of days divided by 365

$\inline&space;\Rightarrow$ Jan (31-13) = 18 days

Feb               = 28 days

March           = 31 days

April             = 30 days

May              = 31 days

June             = 8 days

Total = 146 days

$\inline&space;\therefore$ T = $\inline&space;\frac{146}{365}=\frac{2}{5}$ years

$\inline&space;\therefore$ S.I = $\inline&space;\frac{P\times&space;R\times&space;T}{100}$

= $\inline&space;\frac{12000\times&space;15\times&space;2}{100\times&space;5}$ years

= Rs. 720

A = 12000 + 720 = Rs. 12720

Mohan paid Rs. 12,720 to the money-lender to clear his debt.

371
Q:

What is the SI on Rs.7500/- at the rate of 10% per annum for 5 years?

 A) 3750 B) 2750 C) 1750 D) 750