29
Q:

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

Q:

A person lends Rs. 1540 for five years and Rs. 1800 for four years. If he gets Rs. 1788 as interest on both amounts, what is the rate of interest ?

 A) 14.5% B) 11% C) 12% D) 10.5%

Explanation:

Let the interest rate be r%

We know that,

S.I = PTR/100

=> (1540 x 5 x r)/100  +  (1800 x 4 x r)/100 = 1788

=> r = 178800/14900 = 12%

8 125
Q:

The total simple interest earned on a sum of money increases by Rs. 600 when the rate of interest increases by 2% per annum. If the investment was made for 5 years, find the sum of money that was invested ?

 A) Rs. 6000 B) Rs. 5550 C) Rs. 7500 D) Rs. 6580

Explanation:

Let the sum invested be Rs. P

Let the rate of interest be R% per annum

=> Interest earned for 5 years = (P x 5 x R/100) = PR/20

Now, given that the interest earned increased by Rs. 600 if the Rate increased to (R+2)%

=> SI = (P x 5 x (R+2))/100 = PR/20 + 10P/100

Hence,

PR/20 + 10P/100 = PR/20 + 600

=> P = 6000

Therefore, the sum invested is Rs. 6000

5 113
Q:

Manju borrows Rs.5000 for 2 years at 4% p.a. simple interest from Sudha. She immediately lends it to another person at 6 1⁄4% p.a for 2 years. Find her gain in the transaction per year.

 A) Rs. 101 B) Rs. 98.5 C) Rs. 124.3 D) Rs. 112.5

Explanation:

Manju borrows Rs. 5000 for 2 years at 4% p.a. simple interest

She also lends it at 6 1⁄4% p.a for 2 years

=> Total Gain = 6 1/4% − 4% = 2 1/4%

So her gain in the transaction for 1 year

= The simple interest she gets for Rs.5000 for 1 year at 2 1⁄4% per annum

$\fn_jvn \small \frac{PTR}{100}=\frac{5000x\frac{9}{4}x1}{100}$ = Rs. 112.5/ year.

7 293
Q:

Ronika deposited Rs.7000 which amounted to Rs.9200 after 3 years at simple interest. Had the interest been 2% more. She would get how much ?

 A) 9850 B) 9500 C) 9620 D) 9760

Explanation:

As the interest rate increases by 2%
=> (7000x3x2)/100 = 420
9200
--------
9620

5 330
Q:

If J is the interest on K and K is the interest on L, the rate and time is the same on both the cases. What is the relation between J, K and L  ?

 A) JxJ = KL B) KxK= JL C) LxL = JK D) JKL = 1

Explanation:

Let the Time be 'N' and Rate be 'R'

J = (K x NR)/100 K = (L x NR)/100

J/K = NR/100 K/L = NR/100

J/K = K/L

$\inline \fn_jvn K^{2}$ = JL